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19 /O-
ISCINSECTS AND DISEASE~
A POPULAR ACCOUNT OF THE WAY IN WHICH
INSECTS MAY SPREAD OR CAUSE SOME
OF OUR COMMON DISEASES
WITH MANY ORIGINAL ILLUSTRATIONS FROM
PHOTOGRAPHS
ee ey
RENNIE W. ‘DOANE, A.B.
Assistant Professor of Entomology
Leland Stanford Junior University
NEW YORK
HENRY HOLT AND COMPANY
I9Io
EM\THSONIAHy
FEB 9 1988
GidikaAnie~
CopyvRIGHT, 1910,
BY
HENRY HOLT AND COMPANY
Lublished August, 1910
THE QUINN & BODEN CO. PRESS
RAHWAY, Ne Jp
PREFACE
THE subject of preventive medicine is one that is
attracting world-wide attention to-day. We can hardly
pick up a newspaper or magazine without seeing the
subject discussed in some of its phases, and during the
last few years several books have appeared devoted
wholly or in part to the ways of preventing rather than
curing many of our ills.
Looking over the titles of these articles and books
the reader will at once be impressed with the impor-
tance that is being given to the subject of the relation
of insects to some of our common diseases. As many
of these maladies are caused by minute parasites or
microbes the zodlogists, biologists and physicians are
studying with untiring zeal to learn what they can in
regard to the development and habits of these organisms,
and the entomologists are doing their part by studying
in minute detail the structure and life-history of the
insects that are concerned. ‘Thus many important
facts are being learned, many important observations
made. ‘The results of the best of these investigations
are always published in technical magazines or papers
that are usually accessible only to the specialist.
This little book is an attempt to bring together and
111
1V Preface
place in untechnical form the most important of these
facts gathered from sources many of which are at present
inaccessible to the general reader, perhaps even to
many physicians and entomologists.
In order that the reader who is not a specialist in
medicine or entomology may more readily understand
the intimate biological relations of the animals and
parasites to be discussed it seems desirable to call atten-
tion first to their systematic relations and to review
some of the important general facts in regard to their
structure and life-history. This, it is believed, will
make even the most complex special interrelations of
some of these organisms readily understandable by all.
Those who are already more or less familiar with these
things may find the bibliography of use for more ex-
tended reading.
My thanks are due to Prof. V. L. Kellogg for reading
the manuscript and offering helpful suggestions and
criticisms.
Unless otherwise credited the pictures are from
photographs taken by the author in the laboratory and
field. As many of these are pictures of live specimens
it is believed that they will be of interest as showing
the insects, not as we think they should be, but as they
actually are. Mr. J. H. Paine has given me valuable
aid in preparing these photographs.
R. W. D.
Stanford University, California,
March, rgro.
CONTENTS
CHAPTER I
Meee rTIGNO ANDY IDISEASE (68 ea ek ee a ee
Definition of a parasite, 1; examples among various ani-
mals, 2; Parasitism, 3; effect on the parasite, 4; how a harmless
kind may become harmful, 5; immunity, 6; Diseases caused by
parasites, 7; ancient and modern views, 7; Infectious and con-
tagious diseases, 8; examples, 9; importance of distinguishing,
9; Effect of the parasite on the host, 9; microbes everywhere, 10;
importance of size, 11; numbers, 11; location, 11; mechanical
injury, 12; morphological injury, 13; physiological effect, 13;
the point of view, 14.
CHAPTER II
Peete RUA AND EROTOZOA Ts (iy okey eee UR ue) ell ee
Bacteria, 15; border line between plants and animals, 15;
most bacteria not harmful, 15; a few cause disease, 15; how
they multiply, 15; parasitic and nonparasitic kinds, 17; how a
kind normally harmless may become harmful, 18; effect of the
bacteria on the host, 18; methods of dissemination, 18. Pro-
tozoa, 19; Amoeba, 1g; its lack of special organs, 19; where
it lives, 19; growth and reproduction, 19; Classes of Protozoa,
20; the amoeba-like forms, 20; the flagellate forms, 20; im-
portance of these, 21; the ciliated forms, 22; the Sporozoa or
spore-forming kinds, 22; these most important, 23; abun- -
dance, 23; adaptability, 23; common characters, 24; ability to
resist unfavorable conditions, 24.
Vv
15
v1 Contents
CHAPTER III
PAGE
Ticks AND MITES .. . 26
Ticks, 26; general cee 24; nuit. payee a7. haba
27; life-history, 27; Ticks and disease, 28; Texas fever, 28; its
occurrence in the north, 28; carried by a tick, 29; loss and
methods of control, 31; other diseases of cattle carried by ticks,
31; Rocky Mountain spotted fever, 32; its occurrence, 32;
probably caused by parasites, 32; relation of ticks to this dis-
ease, 33; Relapsing Fever, 33; its occurrence, 34; transmitted
by ticks, 34; Mites, 35; Face-mites, 35; Itch-mites, 36; Harvest-
mites, 37.
CHAPTER IV
How Insects CAUSE OR CARRY DISEASE . . . . | 40
Numbers, 40; importance, 41; losses caused iy insects, 41;
loss of life, 42; The flies, 43; horse-flies, 43; stable-flies, 44;
surra, 45; nagana, 45; black-flies, 46; punkies, 46; screw-worm
flies, 47; blow-flies, 48; flesh-flies, 48; fly larve in intestinal
canal, 49; bot-flies, 50; Fleas, 52; jigger-flea, 53; Bedbugs, 54;
Lice, 54; How insects may carry disease, 55; in a mechanical
way, 55; as oneof the necessary hosts of the parasite, 56.
CHAPTER V
HOUSE-FLIES OR TYPHOID-FLIES .. . 57
The old attitude toward the house-fly, Bo its : ree demi
ing, 58; reasons for the change, 58; Structure, 59; head and
mouth-parts, 60; thorax and wings, 61; feet, 62; How they
carry bacteria, 62; Life-history, 63; eggs, 63; ordinarily laid in
manure, 63; other places, 63; habits of the larve, 64; habits of
the adults, 64; places they visit, 65; Flies and typhoid, 65;
patients carrying the germs before and after they have had the
disease, 65; how the flies get these on their body and distribute
them, 66; results of some observations and experiments, 66;
Flies and other diseases, 68; flies and cholera, 68; flies and tu-
Contents Vii
PAGE
berculosis, 69; possibility of their carrying other diseases, 70;
Fighting flies, 71; screens not sufficient, 71; the larger prob-
lem, 71; the manure pile, 72; outdoor privies, 72; garbage can,
72; codperation necessary, 72; city ordinances, 73; an expert’s
opinion of the house-fly, 73; Other flies, 75; habits of several
much the same but do not enter house as much, 75; the small
house-fly, 75; stable-flies, 75; these may spread disease, 75.
CHAPTER VI
UE PRES NA oA oN Ne ccatiuioli ail d's. PAN NYS leech dacs Wap aM SM ea a a
Numbers, 76; interest and importance, 76; eggs, 77; always
in water, 77; time of hatching, 77; Larve, 78; live only in wa-
ter, 78; head and mouth-parts of larve, 78; what they feed on,
78; breathing apparatus, 79; growth of the larve, 80; Pupe,
80; active but takes no food, 80; breathing tubes, 80; how the
adult issues, 81; The Adult, 81; male and female, 81; how mos-
quitoes ‘‘sing’” and how the song is heard, 82; the palpi, 82;
The Mouth-parts, 83; needles for piercing, 83; How the mos-
quito bites, 84; secretion from the salivary gland, 84; why males
cannot bite, 84; blood not necessary for either sex, 84; The
Thorax, 85; the legs, 85; the wings, 85; the balancers, 85; the
breathing pores, 86; The abdomen, 86; The digestive system,
86; The salivary glands, 87; their importance, 87; effects of a
mosquito bite, 87; probable function of the saliva, 88; How
mosquitoes breathe, 89; Blood, 90; in body cavity, 90; heart, 90;
Classification, 91; Anopheles, 91; distinguishing characters, 92;
eggs, 92; where the larve are found, 93; Yellow fever mosquito,
94; its importance, 94; the adult, 95; habits, 95; habits of the
larvee, 95; Other species, 96; some in fresh water, others in
brackish water, 96; Natural enemies of mosquitoes, 97; how
natural enemies of mosquitoes control their numbers, 98; mos-
quitoes in Hawaii, 98; Enemies of the adults, 99; Enemies of
the larve and pupe, 100; Fighting mosquitoes, 101; fighting
the adult, 102; Fighting the larve, 103; domestic or local
species, 104; draining and treating with oil, 104; combatting
salt-marsh species by draining, 105; by minnows or oil, 105.
Vill Contents
CHAPTER VII
PAGE
MosQuiTors AND MaraRIA . . . . . 106
Early reference to malaria, 106; its pene distributer aoe
theories in regard to its cause, 107; insects early suspected, 107;
The parasite that causes malaria, 108; studies of the parasite,
108; Life-history in human host, i109; its effect on the host, 110;
the search for the sexual generation, 111; The parasite in the
mosquito, 112; review of whole life-history, 115; malaria trans-
mitted only by mosquitoes, 115; Summary, 117; experimental
proof, 118.
CHAPTER VIII
MOSQUITOES AND YELLOW FEVER .. . ai a MS oe
A disease of tropical or semi-tropical doused 120; out-
breaks in the United States, 120; parasite that causes the dis-
ease not known, 121; formerly regarded as a contagious dis-
ease, 122; The yellow fever commission, 123; Dr. Finlay’s
claim, 124; experiments made by the commission, 125; sum-
mary of results, 129; what it means, 130; results in Havana,
131; the fight in New Orleans, 132; In the Panama canal zone,
135; 7n Rio de Janiero, 136; claims of the French commission,
138; habits of stegomyia, 139; breeding habits, 139; possible
results of war against the mosquitoes, 139; Danger of this dis-
ease in the Pacific Islands, r4o.
CHAPTER IX
FLEAS AND PLAGUE) (ho. 00)0) eee te sas! nel teee er ee
Great scourges, 142; the “black death,” 142; old conditions
and new, 143; How plague was controlled in San Francisco,
143; Indian Plague commission, 144; Dr. Simond’s claim,
145; The advisory committee and the new commission, 146;
Results of Dr. Virjbitski’s experiments, 147; Results of various
investigations, 150; structure and habits of fleas, 151; feeding
habits, 152; Common species of fleas, 153; Ground squirrels and
plague, 155; squirrel fleas, 156; Remedies Ms fleas, 157; cats
and dogs, 159. :
Contents 1X
CHAPTER X
PAGE
OTHER DisEasEs, MostLty TROPICAL, KNOWN OR THOUGHT TO
Br TRANSMITTED BY INSECTS . . . : 161
Sleeping Sickness, 161; its occurrence in Rey tow Kaneed
by a Protozoan parasite, 162; the tsetse-fly, 163; Elephan-
tiasis, 164; caused by parasitic worms, 169; their development,
165; how they are transferred to man, 165; effect on the pa-
tient, 166; Dengue, 168; other names, 168; probably trans-
mitted by mosquitoes, 170; Mediterranean fever, 171; cause,
171; may be conveyed by mosquitoes, 171; Leprosy, 171;
caused by a bacteria parasite, 171; possibilities of flies, mos-
quitoes and other insects transmitting the disease, 172; Kala-
azar, 173; transmitted by the bedbug, 173; Orzental sore, 174;
the parasite may be carried by insects, 174.
BIBLIOGRAPHY. . . : ey ears
Parasites and era itiate) Ly ee Piotazoa! 6: Baciena, E775
Insects and disease, 178; Mosquitoes—systematic and general,
179; Mosquito anatomy, 182; Mosquitoes—life-history and
habits, 183; Mosquito fighting, 183; Mosquitoes and disease,
185; Malaria, 186; Yellow fever, 189; Dengue, 192; Filarial
diseases and elephantiasis, 193; Leprosy, 193; Plague, 1094;
Fleas, 198; Typhoid fever, 199; House-flies—anatomy, life-
history, habits, 200; House-flies and typhoid, 202; House-fly
and various diseases, 203; Human myiasis, 207; Stomoxys
and other flies, 208; tsetse-flies, 209; Typanosomes and Try-
panosomiasis, 210; Sleeping sickness, 211; Rocky mountain
fever and ticks, 212; Ticks and various diseases, 213; Kala-
azar and bedbugs, 216; Text or reference books, 216; Miscel-
laneous articles, 218.
<r
sane givers |
. | Ree as
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FIG.
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ILLUSTRATIONS
AN ARTIFICIAL LAKE, NEARLY DRY AND PARTLY
FILLED WITH RUBBISH, HAS BECOME A BREEDING-
GROUND FOR DANGEROUS MOSQUITOES . . Frontispiece
RUESMIBRG VM Mier ee fer eat ie hued ae ea
SBE} eS eee RO ta PR ae
Trichina spiralis, . . . . sy Rea nica
AN EXTERNAL PARASITE, A BIRD-LOUSE (iepenets
POLOD ie wh eee less
AN INTERNAL PARASITE, A TACHINA FLY n (Blephoer:
peza adusta) . COMO CBRN SENPD RTL 4
Work OF AN INTERNAL PARASITE, PUSS-MOTH LARVA
PARASITIZED BY A SMALL ICHNEUMON FLY
TYPHOID FEVER BACILLI . . .
CDi Mel iaeal cll son ine
PERE IL UINEUS Se Tae aS ORT ee nN og eae g
Spirocheta duttont
MGOMEMUICCU EME Sic tis idee he Sha) Sect helt
| A LM Ka AIM i MD lg ote Eliot NEP y aha
PATHOGENIC PROTOZOA; A GROUP OF INTESTINAL
PARASITES . .. . SP Oe ate
CASTOR-BEAN TICK (I hades Ay SPSL hid
') DPKAS VEVER TICK... '*. OR ae
TEXAS FEVER TICK (Margaro leas anmiolas way Be
Amblyomma variegatum . .* 6 2s ee
Ormithodoros moubata . . . aaah
THE FOLLICLE MITE (Demodex folliculorum) Paste
20. ITcH-MITE (Sarcopies scabiet) . .
21. HARVEST-MITES OR “‘JIGGERS”’ . Prey ae Ne
22. HoRSE-FLY (Tabanus punctifer) . . . . 2. e
xl
PAGE
2
2
2
Xl
Fic.
Fie.
Fic.
Fic.
Fic.
Fic.
Fic.
FIG.
FIc.
Fic.
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FIG.
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FIG.
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FIc.
FIG.
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Fic.
Fic.
Fic.
Fic.
Fic.
FIG.
Fic.
Fic.
FIG.
Fic.
Fic.
Fic.
Fic.
Illustrations
. STABLE-FLY (Stomoxys calcitrans) . .
. A BLACK-FLY (Simulium sp.) . Peet 2,4
. SCREW-WoORM FLY (Chrysomyia maceenee
. BLow-FLy (Calliphora vomitoria)
. BLUEBOTTLE FLY (Lucilia sericata)
. FLESH-FLY (Sarcophaga sp.) . Se ae ih
. “THE LITTLE HOUSE-FLY” sti canicu-
laris) .
. HORSE BOT-FLY (Gast pitas equi. )
. OX-WARBLE FLY (Hypoderma lineata)
. SHEEP BOT-FLY (Gastrophilus nasalis) SNe
. CHIGO OR JIGGER-FLEA, MALE 2 eens pene-
trans)
. CHIGO, FEMALE DISTENDED WITH EGGS
. BEpBuG (Cimex lectularis)
. Bopy-LousE (Pediculus vestimentt)
. ONE USE FOR THE HOUSE-FLY
. THE HOUSE-FLY (Musca domestica)
. HEAD OF HOUSE-FLY SHOWING EYES, ANTENNZ AND
MOUTH-PARTS .
. PROBOSCIS OF HOUSE-FLY, SIDE VIEW .
. LOBES AT END OF PROBOSCIS OF HOUSE-FLY SHOWING
CORRUGATED RIDGES
. WING OF HOUSE-FLY ... ae
. WING OF STABLE-FLY (Stomoxys ‘lee
. WING OF HOUSE-FLY SHOWING PARTICLES OF DIRT
ADHERING TO IT
. LAST THREE SEGMENTS OF LEG OF HOUSE-FLY .
. FOOT OF HOUSE-FLY .
. LARVA OF HOUSE-FLY .
. BARNYARD FILLED WITH MANURE
. DIRTY STALIS .
. PUPA OF HOUSE-FLY
. HEAD OF STABLE-FLY
. MASS OF MOSQUITO EGGS (Theobaldia secu)
. MOSQUITO EGGS AND LARV& (T. incidens)
. Mosquito Larva (T. incidens), DORSAL VIEW .
Fic.
Fic.
FIG.
FIG.
FIG.
FIG.
FIG.
Fic.
Fic.
Fic.
FIG.
FIG.
FIG.
Fic.
FIG.
FIG.
FIG.
FIG.
FIG.
Fic.
FIG.
FIG.
FIG.
FIG.
FIG.
Fic.
FIe.
Fic.
FIc.
Fic.
57-
58.
59-
60.
62.
a
. DIAGRAM TO SHOW THE ALIMENTARY CANAL AND
Illustrations
. EGGS, LARVZ AND PUP OF MOSQUITOES (T. inci-
dens)... EVAR Me VEAL aD
. LARVA OF MOSQUITO (I. LION yi dela ARAN hac Ne ct
MOSQUITO LARVZ AND PUP (T. incidens) . . .
ANOPHELES LARV (A. maculipennis) . . . . .
Mosquito puPz (T. incidens) .
Mosouito pupa (T. incidens) .
. MOSQUITO LARV AND PUP& (T. aieetane)
A FEMALE MosQuUITO (TI. incidens.) .
. AMALE MOSQUITO (T. incidens) .
. HEAD AND THORAX OF FEMALE MOSQUITO ‘Ooliee:
tatus lativittatus) . . . :
. HEAD AND THORAX OF MALE MOSQUITO (0. “Tbsapiites
ee Snr eis
. HEAD OF FEMALE MOSQUITO. . . . Saye ine
. CROSS-SECTION OF PROBOSCIS OF FEMALE AND MALE
MOSQUITO .. . so Chae ui et
. WING OF MOSQUITO (O. Weesiaivusy: BP ath Dated oh ie Bie
END OF MOSQUITO WING HIGHLY MAGNIFIED
SALIVARY GLANDS OF A MOSQUITO .. .
. SALIVARY GLANDS OF MOSQUITOES. . . u% ...
. HEADS OF CULICINZ MOSQUITOES .
. HEADS OF ANOPHELINZ MOSQUITOES
. WING OF Anopheles maculipennis .
. WING OF Theobaldta incidens . ~ 2. 1 es ws
. A NON-MALARIAL MOSQUITO (T. incidens), MALE,
SLANDING: ON, THE: WALL) iii tes ee) sey) 0) se) ae
. FEMALE OF SAME. . Wal
. A MALARIAL MOSQUITO (A. meuioeneios oe
STANDING ON THE WALL .......
. FEMALE OF SAME. ‘ pales
. EGG oF Anopheles, SIDE VIEW . . . 1. s
. EGG OF ANOPHELES, DORSAL VIEW. ... .
. ANOPHELES LARV= oP) ent da all CeiR vee OSU me
. ANOPHELES LARVZE ... SVR Reale
. ANOPHELES LARVA, DORSAL VIEW . .....-.
Xiil
PAGE
XIV
FIG.
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FIG.
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FIG.
FIG.
FIG.
FIG.
FIG.
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FIG.
FIG.
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FIG.
FIG.
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FIG.
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85.
86.
87.
88.
89.
go.
ol.
95-
96.
Illustrations
ANOPHELES PUPZ RESTING AT SURFACE OF WATER .
SALT-MARSH MOSQUITO (Ochlerotatus lativitiatus);
MALE... 2027 2 40 Dee
SALT-MARSH MOSQUITO (O. lativitiatus); FEMALE . .
Top-MINNOW (Mollienisia latipinna). . . ...
DRAGON-FLIES + 200.0 880) 0) Ger
THE YOUNG (NYMPH) OF A DRAGON-FLY . ....
THE CAST SKIN (exuv@) OF A DRAGON-FLY NYMPH
DIVING-BEETLES AND BACK-SWIMMERS .... .
Kixurriso (Fundulus heteroliatus). . . . 2...
STICKLEBACK (A peltes quadracus) . . . . . « .
AN OLD WATERING-TROUGH, AN EXCELLENT BREEDING-
PLACE FOR MOSQUITOES . . ©.) (=) Sena
HoRSE AND CATTLE TRACKS IN MUD FILLED WITH
RATAN Ne) M2) hs Se ene ian
97. A MALARIAL MOSQUITO (Anaphene' macnibpeonan
98.
99-
Ico.
Ior.
102.
103.
104.
105.
106.
107.
108.
109.
IIo.
III.
RATE Ufo 00., » ele eh Oe ane
A MALARIAL esau (A. maculibennes) FEMALE .
DIAGRAM TO ILLUSTRATE THE LIFE-HISTORY OF THE
MALARIAL PARASITE « . . os. CES ine mane
MALARIAL MOSQUITO (A. micscitepeniiee ON THE WALL
MALARIAL MOSQUITO (A. maculipennis) STANDING ON
IANEABUE SUAS! na ie . NS eR
SALT-MARSH MOSQUITO (0. lativittatus) STANDING ON
A TABLE es s se e ° e es ° e es . s
ANOPHELES HANGING FROM THE CEILING . . .
YELLOW FEVER MOSQUITO (Siegomyiacalopus) . .
RatT-FLEA (Lemopsylla cheopis); MALE . .. .
RAT-FLEA (L. cheopis); FEMALE . . . . . «+ +
HEAD OF RAT-FLEA SHOWING MOUTH-PARTS .. .
HUMAN-FLEA (Pulex irritans); MALE . . . . . -
HUMAN-FLEA (P. irritans); FEMALE . .... .
MousE-FLEA (Ctenopsyllus musculi); FEMALE . . .
TRYPANOSOMA GAMBIENSE . . . . « 2 we eo
Fic. I I 2 e TSETSE-F LY e e e e e ° e ° e ° ° e . e
PAGE
93
98
908
99
99
100
Ioo
Ior
102
102
103
108
108
109
IIo
Iit
Itt
118
118
122
152
152
153
153
156
156
164
164
Poel ilS AND DISEASE
CHAPTER I
PARASITISM AND DISEASE
PARASITES
: aA|HE dictionary says that a parasite is a
Saeae| living organism, either animal or plant,
Al ie that lives in or on some other organism
from which it derives its nourishment
for a whole or part of its existence. This defini-
tion will serve as well as any, as it seems to include
all the forms that might be classed as parasites.
As a general thing, however, we are accustomed
to think of a parasite as working more or less in-
jury to its host, or perhaps we had better say
that if it does not cause any irritation or ill ef-
fects its presence is not noted and we do not think
of it at all.
As a matter of fact the number of eraciae
organisms that are actually detrimental to the wel-
fare of their hosts is comparatively small while the
number of forms both large and small that lead
2 Insects and Disease
parasitic lives in or on various hosts, usually doing
no appreciable harm, often perhaps without the
host being aware of their presence, is very great in-
deed.
Few of the higher animals live parasitic lives.
The nearest approach to a true parasite among
the vertebrates is the lamprey-eel (Fig. 1) which
attaches itself to the body of a fish and sucks
the blood or eats the flesh Among the Crus-
taceans, the group that includes the lobsters and
crabs, we find many examples of parasites, the
most extraordinary of which is the curious crab
known as Sacculina (Fig. 2). In its early stages
this creature is free-swimming and looks not
unlike other young crabs. But it soon attaches
itself to another crab and begins to live at the ex-
pense of its host. ‘Then it commences to undergo
remarkable changes and finally becomes a mere
sac-like organ with a number of long slender root-
like processes penetrating and taking nourishment
from the body of the unfortunate crab-host.
The worms furnish many well-known examples
of parasites, whole groups of them being especially
adapted to parasitic life. The tapeworms, com-
mon in many animals and often occurring in man,
the roundworms of which the trichina (Fig. 3) that
causes ‘‘measly’’? pork is a representative, are
Fic. 1—A lamprey. (After Goode.)
Fic. 2—Sacculina; A, parasite attached to a crab; B, the active larval con-
dition; C, the adult removed from its host. (After Haeckel.) |
Fic. 3—Trichina spiralis encysted in muscle of a pig. (From Kellogg’s
Elementary Zool.)
FIG. 6
Fic. 4—An external parasite, a bird-louse (Lipeurus ferox).
Fic. 5—A tachina fly (Blepharipeza adusta) the larva of whicn
is an internal parasite.
Fic. 6—Work of an internal parasite, puss-moth larva parasi-
tized by a small ichneumon fly.
these.
Parasitism and Disease 2
familiar examples. These and a host of others
all show a very high degree of specialization fit-
ting them for their peculiar lives in their hosts.
From among the insects may be selected interest-
ing examples of almost all kinds and degrees of
parasitism, temporary, permanent, external, in-
ternal (Figs. 4, 5, 6). Among them is found, too,
_ that curious condition known as hyperparasitism
where one animal, itself a parasite, is preyed upon
by a still smaller parasite.
““The larger fleas have smaller fleas
Upon their backs to bite um,
These little fleas still smaller fleas
And so ad infimitum.”
Coming now to the minute, microscopic, one-
celled animals, the Protozoa, we find entire
groups of them that are living parasitic lives, de-
pending wholly on one or more hosts for their ex-
istence. Many of these have a very remarkable
life-history, living part of the time in one host,
part in another. The malarial parasite and others
that cause some of the diseases of man and do-
mestic animals are among the most important of
PARASITISM
Among all these parasites, from the highest to
the lowest the process that has fitted them for a
4 Insects and Disease
parasitic life has been one of degeneration. While
they may be specialized to an extreme degree in
one direction they are usually found to have some
of the parts or organs, which in closely related
forms are well developed, atrophied or entirely
wanting. As a rule this is a distinct advantage
rather than a disadvantage to the parasite, for
those parts or organs that are lost would be use-
less or even in the way in its special mode of life.
Then, too, the parasite often gives up all its inde-
pendence and becomes wholly dependent on its
host or hosts not only for its food but for its dissem-
ination from one animal to another, in order that
the species may not perish with the host. But in
return for all this it has gained a life of ease, free
from most of the dangers that beset the more inde-
pendent animals, and is thus able to devote its
whole time and energy to development and the
propagation of the species.
We are accustomed to group the parasites that
we know into two classes, as harmful or injurious
and as harmless, the latter including all those
kinds that do not ordinarily affect our well-being in
any way. But such a classification is not always
satisfactory or safe, for certain organisms that to-
day or under present conditions are not harmful
may, on account of a great increase in numbers or
Parasitism and Disease 5
change of conditions, become of prime importance
to-morrow. An animal that is well and strong may
harbor large numbers of parasites which are living
at the expense of some of the host’s food or energy
or comfort, yet the loss is so small that it is not
noticed and the intruders, if they are thought of at
all, are classed as harmless. Or we may at times
even look upon them as beneficial in one way or
another. ‘‘A reasonable amount of fleas is good
fora dog. ‘They keep him from brooding on being
a dog.”’ :
But should these parasites for some reason or
other increase rapidly they might work great harm
to the host. Even David Harum would limit the
number of fleas on a dog. Or the animal might
become weakened from some cause so that the
drain on its resources made by the parasites, even
though they did not increase in numbers, would
materially affect it.
Perhaps the most serious way in which para-
sites that are usually harmless may become of
great importance is illustrated by their introduc-
tion into new regions or, as is more often the case,
by the introduction of new hosts into the region
where the parasites are found. Under normal con-
ditions the animals of a given region are usually
immune to the parasites of the same region. That
6 Insects and Disease
is, they actually repel them and do not suffer
them to exist in or on their bodies, or they are
tolerant toward them. In the latter case the
parasites live at the expense of the host, but the host
has become used to their being there, adapted to
them, and the injury that they do, if any, is neg-
ligible. |
But when a new animal comes into the region
from some other locality the parasites may be ex-
tremely dangerous to it. There are many strik-
ing examples of this. Most of the people living
in what is known as the yellow fever belt are im-
mune to the fever. They will not develop it even
under conditions that would surely mean infection
for a person from outside this zone. Certain of
our common diseases which we regard as of little
consequence become very serious matters when in-
troduced among a people that has never known
them before. The cattle of the southern states
are immune to the Texas fever, but let northern
cattle be sent south or let the ticks which transmit
the disease be taken north where they can get on
cattle there, and the results are disastrous.
Another striking example and one that is at-
tracting world-wide attention just now is the
trypanosome that is causing such devastation
among the inhabitants of central Africa. With the
Parasitism and Disease 7
advent of white men into this region and the conse-
quent migration of the natives along the trade
routes this parasite, which is the cause of sleeping
sickness, is being introduced into new regions and
thousands upon thousands of people are dying as a
result of its ravages.
DISEASES CAUSED BY PARASITES
Some two hundred years ago, after it became
known that minute animal parasites were associ-
ated with certain diseases and were the cause of
them, it rapidly came to be believed that all our ills
were in some way caused by such parasites, known
or unknown. Further study and investigation
failed to reveal the intruders in many instances
and so it began to be doubted whether after all
they were responsible for much that had been laid
at their doors. Then after it was discovered that
minute plant parasites, bacteria, were responsible
for many diseases they in turn began to be accused
of being the cause of most of the ills that the flesh
is heir to.
In later years we have come to adopt what seems
to be a more reasonable view, for we can see and
definitely prove that neither of these extreme views
was correct but that there was much truth in each
of them. ‘To-day we recognize that certain diseases,
8 Insects and Disease
such as typhoid, cholera, tuberculosis and many
others, are caused by the presence of bacteria in the
body, and it is just as definitely known that such
maladies as malaria and sleeping sickness are
caused by animal parasites.
Then there is a long list of other epidemic
diseases, such as smallpox, measles and scarlet
fever, the exact cause of which has not been de-
termined. Many of these are believed to be due
to micro-organisms of some kind, and if so they
will almost certainly sooner or later be found.
~ Curiously enough most of the diseases in this last
class and many of those in the first are contagious,
while all that are caused by animal parasites are,
as far as is known, infectious but not contagious.
INFECTIOUS AND CONTAGIOUS DISEASES
It is important that we keep in mind this distinc-
tion. By contagious diseases are meant those that
are transmitted by contact with the diseased per-
son either directly, by touch, or indirectly by the
use of the same articles, by the breath or effluvial
emanations from the body or other sources. Small-
pox, measles, influenza, etc., are examples of this
group. By infectious diseases are meant. those
which are disseminated indirectly, that is, in a
roundabout way by means of water or food or
Parasitism and Disease 9
other substances taken into or introduced into the
body in some way. Typhoid, malaria, and yellow
fever, cholera and others are examples of this class.
Thus it is evident that all of the contagious dis-
eases may be infectious, but many of the infectious
diseases are not as a rule contagious, although some
of them may become so under favorable con-
ditions.
Just one example will show the importance of
knowing whether a disease is contagious or in-
fectious. Until a few years ago it was believed
that yellow fever was highly contagious and every
precaution was taken to keep the disease from
spreading by keeping the infected region in strict
quarantine. This often meant much hardship and
suffering and always a great financial loss. We
now know that it is infectious only and not con-
tagious, and that all this quarantine was unneces-
sary. The whole fight in controlling an outbreak
of yellow fever or in preventing such an outbreak
is now directed against the mosquito, the sole
agent by which the disease can be transmitted
from one person to another.
EFFECT OF THE PARASITE ON THE HOST
We have seen how a few parasites in or on an
animal do not as a rule produce any appreciable
10 Insects and Disease
ill effects. ‘This is of course a most fortunate
thing for us, for the parasitic germs are everywhere.
There is perhaps ‘“‘more truth than poetry” in
the following newspaper jingle:
“Sing a song of microbes,
Dainty little things,
Eyes and ears and horns and tails,
Claws and fangs and stings.
Microbes in the carpet,
Microbes in the wall,
Microbes in the vestibule,
Microbes in the hall.
Microbes on my money,
Microbes in my hair,
Microbes on my meat and bread,
Microbes everywhere.
Microbes in the butter,
Microbes in the cheese,
Microbes on the knives and forks,
Microbes in the breeze.
Friends are little microbes,
Enemies are big,
Life among the microbes is—
Nothing ‘infra dig.’
Fussy little microbes,
Millions at a birth,
Make our flesh and blood and bones,
Keep us on the earth.”
While of course most of these microbes are to be
regarded as absolutely harmless and some as very
useful, many have the power to do much injury if
Parasitism and Disease II
the proper conditions for their rapid develop-
ment should at any time exist. While the size of
the parasite is always a factor in the damage that
it may do to the host the factor of numbers is
perhaps of still greater importance because of the
power of very rapid multiplication possessed by so
many of the smaller forms.
Certain minute parasites in the blood may cause
little or no inconvenience, but should they begin
to multiply too rapidly some of the capillaries may
be filled up and trouble thus result. Or take some
of the larger forms. A few intestinal worms may
cause no appreciable effect on the host, but as soon
as their numbers increase serious conditions may
come about simply by the presence of the great
masses in the host even if they were not robbing it
of its nourishment. Many instances are known
where such worms have formed masses that com-
pletely clogged up the alimentary canal. Such in-
juries as these may be regarded as mechanical in-
juries. Some parasites injure the host only when
they are laying their eggs or reproducing the young.
These may clog up passages or some of them may
be carried to some more sensitive part of the body
where the damage is done. The guinea-worm of
southwestern Asia and of Africa lives in the body
of its host for nearly a year sometimes attaining
12 Insects and Disease
a great length and migrating through the connect-
ive tissue to different parts of the body causing no
particular inconvenience until it is ready to lay its
eggs when it comes to the surface and then great
suffering may result. The African eye-worm is an-
other example of a parasite causing mechanical
injury only at certain times. It works in the
tissues of the body sometimes for a long while,
doing no harm unless it finds its way to the connect-
ive tissue of the eyeball.
It is known that many of the germs which cause
diseases cannot get into the body unless the pro-
tecting membranes have first been injured in some
way. ‘Thus the germs that cause plague and lock-
jaw find their way into the system principally
through abrasions of the skin. Many physicians
have come to believe that the typhoid fever germ
cannot get into the body from the intestine where it
is taken with our food or drink unless the walls of
the intestine have been injured in some way. It is
well known that of the many parasites that inhabit
the alimentary canal some rasp the surface and
others bore through into the body cavity. This in
itself may not be a serious thing, but if the mechani-
cal injury thus caused opens the way for malignant
germs, baneful results may follow. Even that
popular disease appendicitis is believed to be due
Parasitism and Disease 13
sometimes to the injury caused by the work of
parasites in the appendix.
Parasites may cause morphological or struc-
tural changes in the tissues of their hosts. The
stimulation caused by their presence may result
in swellings or excresences or other abnormal
growths. Interesting examples of this are to be
found in the way in which pearls are formed in
various mollusks. In the pearl oysters of Ceylon
occur some of the best pearls. If these are care-
fully sectioned there may usually be found at the
center the remains of certain cestode larve whose
presence in the oyster caused it to deposit the
nacreous layers that make up the pearl. Other
parasites cause similar growths in various shell-
fish. The great enlargements of the arms or legs
or other parts of the body seen in patients affected
with elephantiasis is an abnormal growth due to
the presence of the parasitic filare in some of the
lymph-glands where they have come to rest.
Finally, the parasite may exert a direct physio-
logical effect on the host. This is evident when the
parasite demands and takes a portion of the
nourishment that would otherwise go to the build-
ing up of the host. Sometimes this is of little im-
portance, but at other times it may be a matter of
life or death to the infected animal. The physio-
14 Insects and Disease
logical effect produced may be due to the toxins or
poisonous matters that are given off by the parasite
while it is living in the host’s body. Thus it is be-
lieved that the malarial patients usually suffer less
from the actual loss of red blood-corpuscles that
are destroyed by the parasite than they do from
the effects of the poisonous excretions that are
poured into the circulation when the thousands
of corpuscles break to release the parasites.
One other point in regard to the relation of the
parasite to its host and this part of the subject may
be dismissed. From our standpoint we look upon
the presence of parasites in the body as an ab-
normal condition. From a biological standpoint
their presence there is perfectly normal; it is a
necessary part of their life. We think that they
have no business there, but from the viewpoint of
the parasites their whole business is to be just
there. If they are not, they perish. And when we
take a dose of quinine or other drug we are killing
or driving from their homes millions of these little
creatures who have taken up their abode with us
for the time being. But they interfere with our
health and comfort, so they must go.
ase
CHAPTER, it
BACTERIA AND PROTOZOA
BACTERIA
aN the border line between the plant and
Mi! the animal worlds are many forms which
Bi; possess some of the characteristics of
both. Indeed when an attempt is made
to separate all known organisms into two groups
one is immediately confronted with difficulties. In
looking over the text-books of Botany we will find
that certain low forms are discussed there as belong-
ing with the plants, and on turning to the manuals
of Zodlogy we will find that the same organisms are
placed among the lowest forms of animals. The
question is of course of little actual importance
from certain points of view. It serves, however, to
show the close relation of all forms of life, and from
a medical standpoint it may be of very great im-
portance owing to the difference in the life-habits,
methods of reproduction and methods of trans-
mission of many of the forms that cause disease.
We have already seen that none of the diseases that
5
16 Insects and Disease
are caused by animal parasites is contagious, while
many of those caused by bacteria are both con-
tagious and infectious.
Just over on the plant side of this indefinite
border line are the minute organisms known as
bacteria. ‘Their numbers are infinite and they are
found everywhere. ‘The majority of them are
beneficial to mankind in one way or another, but
some of them cause certain of the diseases that we
will have to discuss later so attention may be called
here to a few of the important facts in regard to
their organization and life-history in order that we
may better understand how they may be so easily
transferred from one host to another.
Although these bacilli are so extremely minute
(Fig. 7), some of them so small that they cannot be
seen with the most powerful microscopes, they
differ in size, shape, methods of division and spore-
formation. Each species makes a characteristic
growth on gelatin, agar or other media upon which
it may be cultivated. In this way as well as by the
inoculation of animals the presence of the ultra-
microscopic kinds may be demonstrated.
The method of reproduction is very simple.
They increase to a certain point in size, then divide.
This growth and division takes place very rapidly.
Twenty to thirty minutes is sufficient time in some
ee
Bacteria and Protozoa 17
cases for a just-divided cell to attain full size and
divide again. Thus in a few days time the number
of bacteria resulting from a single individual would
be inconceivable if they should all develop.
Fortunately for us, however, they do not all
multiply so rapidly as this and besides there are
natural checks, not the least of which are the sub-
stances given off by the bacteria themselves in
their growth and development. Such excretions
often serve to inhibit further multiplication. Some-
times, though not often, they form spores which
not only provide for a more rapid multiplication,
but enable the organism to live under conditions
that would otherwise prove fatal to it.
Bacteria may be conveniently grouped under
two heads: those that live upon dead organic mat-
ter, known as the saprophytic forms, and those
that are found in living plants or animals, the true
parasites. Such a grouping is not always entirely
satisfactory, for many of the kinds that live sapro-
phytically under normal conditions may become
parasitic if opportunity offers, and also many of
those that are usually regarded as parasitic may be
grown in cultures of agar or other media, under
which conditions they may be regarded as living
saprophytically.
It is this power of easily adapting themselves
18 Insects and Disease
to different conditions that makes many of the
kinds dangerous. ‘The bacillus which causes
tetanus or lockjaw will illustrate this. It is a
rather common bacillus in soil in many localities.
As long as it remains there it is of no special im-
portance, but if it is introduced into the body
through a scratch or any other wound it becomes
a very Serious matter.
We may say, then, that the effect the bacillus has
on the host depends largely on the host. Not only
does it depend on what the host is, but the particu-
lar condition of the host at the time of infection
is of importance. Children are subject to many
diseases that adults seldom have. Hunger, thirst,
- fatigue, exposure and other factors may make a
person susceptible to the actions of certain bac-
teria that would be harmless under other condi-
tions. !
The minute size and great numbers of the bac-
teria make their dissemination a comparatively
simple matter. They may be carried in the air
as minute particles of dust; they may be carried
in water or milk; they may be carried on the cloth-
ing or on the person from one host to another, or
_ they may be disseminated in scores of other ways.
In other chapters, particularly the one dealing with
- the house-fly and typhoid, we shall see how it is
Bacteria and Protozoa 19
that insects are often important factors in spread-
ing some of the most dreaded of the bacterial dis-
eases.
THE PROTOZOA
The Protozoa, or one-celled animals, belonged to
an unknown world before the invention of the
microscope. The first of these instruments enabled
the early observers to see some of the larger and
more conspicuous members of the group and each
improvement of the microscope has enabled us to
see more and more of them and to study in detail
not only the structure but to follow the life-history
of many of them.
The Ameba. With some, as the common amceba
(Fig. 8), a minute little form that is to be found in
the slime at the bottom of almost any body of
water, the life-history is extremely simple. The
organism itself consists of a minute particle of
protoplasm, a single cell with no definite shape or
body-wall and no specialized organs or apparatus
for carrying on the life-functions. It lives in the
slime or ooze in fresh or salt water, takes its food
by simply flowing over the particle that is to be
ingested, grows to a certain limit of size, then di-
_vides into two more or less equal parts, each part
becoming a new animal that goes on with its de-
20 Insects and Disease
velopment as did the parent form. This process
of growth and division may go on for many gener-
ations, but cannot continue indefinitely unless there
is a conjugation of two separate individuals. This
process of conjugation is just the opposite to that
of division. ‘Two amceba flow together and be-
come one. It seems to rejuvenate the organism so
that it is able to go on with its division and thus
fulfil its life-mission which is the same for these
lowly animals as with the higher, that of perpetu-
ating the species.
Classes of Protozoa. The group or Phylum Pro-
tozoa is divided into four smaller groups or classes.
The amceba belongs to the lowest of these, the
Rhizopoda. Rhizopoda means ‘‘root-footed,” and
the name is applied to these animals because most
of them move about by means of root-like processes
known as pseudopodia or ‘‘false feet.” This is
by far the largest class and contains thousands of
forms, mostly living in salt water but there are
many fresh-water species. They are non-parasitic,
but some of them by their presence in the body
may cause such diseases as dysentery, etc.
The next class which may be known as the whip-
bearers (Mastigophora) includes those Protozoa
that move by fine undulating processes called
flagella. One of the common representatives: of
4
4
i
:
Fic. 7—Typhoid Fever bacilli. (After
Muir and Ritchie.)
Mages?
58 eee ee
Fic. 8—Ameba, showing the forms assumed by a single individual in
four successive changes. (From Kelloge’s Elementary Zodl.)
Fic. 9—Luglina virdis. (After Saville Kent.)
Fic. 10—Spirochaeta duttoni, x 4500, (After Breinl
and Carter. )
Bacteria and Protozoa 21
this class is the little green Euglena (Fig. 9), whose
presence in standing ponds and puddles often im-
parts a greenish color to the water. Then in the
salt water near the surface there are often myri-
ads of minute Noctiluca whose wonderfully phos-
phorescent little bodies glow like coals of fire when
the water is disturbed at night. Although this class
contains fewer forms than the preceding some of
these have within recent years been found to be of
great importance because they live as parasites on
man and other animals. ‘The trypanosome whose
presence in the blood and tissues of the patient
causes that dreadful disease which ends in sleeping
sickness belongs here as well as do several other
similar kinds that produce serious troubles for va-
rious mammals and birds. ‘The Spirocheta, about
which there has been so much recent discussion,
also belong here. ‘These are simple spiral-like
forms (Fig. 10), that are sometimes classed with
the simple plants, bacteria, but Nuttall and others
have shown very definitely that they should be
classed with the simplest animals, the Protozoans.
These are the cause of relapsing fevers in man
and of several diseases of domestic animals. It is
believed by certain eminent zodlogists that when
the germ that causes yellow fever is discovered it
will be found to belong to this group.
22 Insects and Disease
The members of the class Infusoria, so called
because they were early found to be abundant in
various infusions, are characterized by numerous
fine cilia or hair-like organs by means of which the
organism moves about and procures its food. The
well-known ‘“‘slipper animalcule” (Paramoecium)
(Fig. 11), and the “bell-animalcule” (Vorticella)
(Fig. 12) are two common representatives. The
Paramoecia were the animals mostly used by Jen-
nings in his wonderfully interesting experiments
on the behavior of these lowly forms of life. He
showed that they always reacted in a certain defi-
nite way in response to particular stimuli, and he
was led to believe that he could see “‘what must
be considered the beginnings of intelligence and
of many other qualities found in the higher ani-
mals.”” A species of Vorticella was probably the
first Protozoan that was ever observed. An old
Dutch microscopist, Anton von Leeuwenhoek, in
1675, while studying with lenses of his own manu-
facture, discovered and described forms which un-
doubtedly belong to this genus. Few if any of the
Infusoria are pathogenic, although some are said
to be associated with certain intestinal diseases
both in man and the lower animals (Fig. 13).
The last class, the Sporozoa, or the spore-forming
animals, while small in the number of known spe-
i
! } Wy
Whig Ny, Wh;
EGY
Fic. 11—Paramoecium. (From Kellogg’s Elementary Zo0l.)
Fic. 12—Vorticella, one individual with the stalk coiled, the other
with the stalk extended. (From Kellogg’s Elementary Zool.)
Fic. 13—Pathogenic Protozoa; a group of intestinal parasites.
A, B, Megastoma entericum, C, Balantidum entozoon. (After Calkins.)
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Bacteria and Protozoa 23
cies, only about three hundred kinds being known,
is extremely important. A number of diseases in
man and other animals are due to the presence of
these Sporozoans, for they are all parasitic. Few
if any animals are exempt from their attacks.
They even attack other minute Protozoa. One
hundred and fifty-seven species have been recorded
as attacking insects, one hundred species attack
birds, fifty-two reptiles, eighty crustaceans, twenty-
two fish, and so through the list. ‘Ten have been
recorded as attacking man. In some instances
the parasite is always present in the host and some
hosts may harbor several different species of
Sporozoa.
Very little work had been done on this group of
parasites prior to 1900. Since that time most of
the species that we now know have been discov-
ered, and within the last few years the life-histories
of many of these have been worked out quite com-
pletely. No other group of animals is being studied
more to-day by both the physicians and biologists.
The Sporozoa vary greatly in appearance,
organization and life-history. They are so very
plastic that they can adapt themselves readily to
their various hosts, hence we have a great variety
of forms. But they all agree in certain characters;
all take their food and oxygen and carry on ex-
24 Insects and Disease
cretory processes by osmosis, 7. e., through the
body-wall; all are capable of some kind of locomo-
tion, some have one or more flagella, others move
by a pseudopod movement. Some are capable of
moving from cell to cell in the body as do the
white blood-corpuscles. ‘They all agree in the pro-
duction of spores—hence the name.
At certain stages in their development the nu-
cleus within the body of the organism divides again
and again until there are a great many daughter
nuclei, each accompanied by a small mass of proto-
plasm, often inclosed in a little sac or cyst of its
own. This is the process of spore-formation and
we see that from a single individual we may have
by division, not two animals as in the ameeba, but
a score or more of them. ‘The little cysts or
capsules that inclose them enable them to resist
without injury many vicissitudes that would other-
wise destroy them. They may dry up or freeze or
lie for a long time in the ground or water until the
time comes when they are introduced into another
host. ;
The class Sporozoa is divided into five small
groups or orders. Nearly all of these contain
forms that are of more or less importance, but the
ones that live in the blood-cells (Hl @mosporidiuda)
are of the most interest to us because the parasites
Bacteria and Protozoa 25
that cause the malarial fevers and various other
diseases belong here. These are dependent on two
hosts for their existence, the sexual generation
usually occuring in an insect or other invertebrate
and the asexual generation in some vertebrate.
CHAPTER IIT
TICKS AND MITES
QeSHQiHE other group or Phylum of animals
ra a4 with which we will be particularly con-
| Us cerned is known as the Arthropoda,
which means “jointed-feet” and in-
cludes the crayfish, crabs, spiders, mites, ticks and
insects. Of these only the last three are of inter-
est to us now. It is customary to speak of spiders,
mites and ticks as insects, but as they have four
pairs of legs, instead of three pairs, in the adult
stage, and as their bodies are not divided into
three distinct regions as in the insects, they are
placed in a different class.
GENERAL CHARACTERS OF TICKS
The ticks are all comparatively large, that is, they
are all large enough to be seen with the unaided
eye even in their younger stages and some grow to
be half an inch long. When filled with blood the
tough leathery skin becomes much distended often
making the creature look more like a large seed
26
Ticks and Mites 27
than anything else (Fig. 14). ‘This resemblance is
responsible for some oF the popular names, such as
“‘castor-bean tick,”
The legs of most lias are comparatively short,
and the head is small so that they are often hardly
noticeable when the body is distended. ‘The suck-
ing beak which is thrust into the host when the
tick is feeding is furnished with many strong re-
curved teeth which hold on so firmly that when one
attempts to pull the tick away the head is often
torn from the body and left in the skin. Unless
care is taken to remove this, serious sores often
result.
Ticks are wholly parasitic in their habits. Some
of them live on their host practically all their lives,
dropping to the ground to deposit their eggs when
fully mature. Others leave their host twice to
molt in or on the ground. The female lays her
eggs, 1,000 to 10,000 of them, on the ground or just
beneath the surface. The young “‘seed-ticks ”’ that
hatch from these in a few days soon crawl up on
some near-by blade of grass or on a bush or shrub
and wait quietly and patiently until some animal
comes along. If the animal comes close enough
they leave the grass or other support and cling to
their new-found host and are soon taking their first
meal. Of course thousands of them are disap-
28 Insects and Disease
pointed and starve before their host appears, but
as they are able to live for a remarkably long time
without taking food their patience is often rewarded
and the long fast ended. |
Those species which drop to the ground to molt
must again climb to some favorable point and wait
for another host on which they may feed for a
while. Then they drop to the ground for a second
molt and if they are successful in gaining a new
host for the third time they feed and develop until
fully mature and the female is ready to lay her
eggs. The Texas fever tick, and some others, as
we shall see, do not drop to the ground to molt but
once having gained a host remain on it until ready
to deposit their eggs.
The young ticks have only six legs (Fig. 15) but
after the first molt they all have eight.
TICKS AND DISEASE
Texas Fever. Ever since stockmen began driving
southern cattle into states further north it has been
noted that the roads over which they were driven
became a source of great danger to northern cattle.
Often 80% to 90% of the native cattle died after
a herd of southern cattle passed through their
region and the losses became so great that both
state and national laws were passed prohibiting
Fic. 14—Castor Bean Tick (Ixodes ricinus)
not fuily gorged.
Fic. 15—vTexas fever tick, just hatched;
has only six legs.
Fic. 16—Texas fever tick (Margaropus an-
nulatus) young adult not fully gorged.
Fic. 17—Amblyomma variegatum several ticks belonging
to this genus transmit Piroplasma which cause vari-
ous diseases of domestic animals.
a an
Ticks and Mites 29
the driving or shipping of southern cattle into
northern states.
But for years the cause of this fever, which came
to be known as the Texas fever, was not known.
The southern cattle themselves seemed healthy
enough and it was difficult to understand how they
could give the disease to the others. It was early
noticed, too, that it was not necessary for the
northern cattle to come in direct contact with the
others in order to contract the disease. Indeed
the disease was not contracted in this way at all.
All that was necessary for them was to pass along
the same roads or feed in the same pastures or
ranges. Still more puzzling was the fact that these
places did not seem to become a source of danger
until some weeks after the southern cattle had
passed over them and then they might remain
dangerous for months.
In 1886 Dr. Theobald Smith of the Bureau of
Animal Industry, United States Department of
Agriculture, found that the fever was caused by the
presence in the infected cattle of a minute Sporo-
zoan parasite (Piroplasma bigeminum). Further
investigations and experiments proved conclusively
that this parasite was transmitted from the infected
to the well animal only by the common cattle tick
now. known as the Texas fever tick (Fig. 16)..
30 Insects and Disease
The infection is not direct, that is, the tick does
not feed on one host then pass to another carrying
the disease germs with it. Unlike many other
ticks the Texas fever tick does not leave its host
until it is fully developed. When the female is full
grown and gorged she drops to the ground and lays
from 2,000 to 4,000 eggs which soon hatch into the
minute ‘‘seed-ticks” which make their way to the
nearest blade of grass or weed or shrub and
patiently wait for the cattle to come along.
If the mother tick had been feeding on an animal
that was infected with the Texas fever parasite,
her body was filled with the minute organisms of
which some found their way into the eggs so that
the young ticks hatching from them were already
infected and ready to carry the infection to the first
animal they fed upon.
It took many years of hard patient work to
learn all this, but the knowledge thus obtained
cleared up much of the mystery in connection
with the occurrence of the fever in the north and,
as we shall see, suggested the possibility of other
diseases being communicated in the same way.
It was found that the southern cattle in the
region where the ticks occur normally, usually
have a mild attack of the disease when they are
young and although they may be infected with the
Ticks and Mites 31
parasite all the rest of their lives it does not affect
them seriously. These cattle are almost always
infected with ticks, and when taken north where
the ticks do not occur naturally and where the cat-
tle are therefore non-immune, some of the mature
ticks drop to the ground and lay their eggs which
in a few weeks hatch out and are ready to infect
any animal that passes by. ‘The northern cattle
not being used to the disease soon sicken and die.
It is estimated that the annual loss due to this
disease and the ravages of the tick:in the United
States is over $100,000,000, so of course most
determined efforts are being made to stamp it out.
Formerly various devices for dipping the tick-
infested cattle into some solution that would kill
the ticks were resorted to, but it was always ex-
pensive and never very satisfactory. The immu-
nizing of the cattle by inoculating them when they
were young with infected blood has been practised.
Very recent investigations have shown that it is
possible and practicable to rid pastures of ticks
by a system of feed-lots and pasture rotation. The
aim is to have as many of the ticks as possible drop
to the ground on land where they may be destroyed
and to so regulate the use of the pasture that the
ticks in all of them may eventually be left to starve.
Several similar diseases of cattle, many of them
32 Insects and Disease
probably identical with Texas fever, occur in other
parts of the world where the losses are sometimes
appalling. Horses, sheep, dogs, and other animals
are also affected with diseases caused by the same
group of Protozoan parasites. Most of them have
been shown to be transmitted by various species of
ticks (Fig. 17) so that from an economical stand-
point these little pests are becoming of prime im-
portance. Not only do they transmit the disease
' germs that infect domestic animals but they are
known to be responsible for at least two diseases
of men, Rocky Mountain spotted fever and the
relapsing fevers.
Spotied Fever. 'The first of these is a disease that
for some years has been puzzling the physicians in
Idaho and Montana and other mountainous states.
A few years ago certain observers recorded finding
Protozoan parasites in the blood of those suffering
from the disease, and although more recent in-
vestigations have failed to confirm these particular
observations it is now quite generally believed that
the disease is caused by some such parasite and that
the organism is transferred from one host to an-
other by certain species of ticks that live on wild
mammals of the region where the disease exists.
Dr. H. T. Ricketts, who has made a special study
of the disease, has shown: :
Ticks and Mites 33
“‘r, That the period of activity of the disease is lim-
ited to the season during which the adult female and
male ticks attack man.
“2, That in practically all cases of this disease it
can be shown that the patient has been bitten by a
ia
i ay 2nat the period between the tick bite and the
onset of the disease in the many animals he has ex-
perimented with corresponds very closely to this period
as observed in man.
“a, That infected ticks are to be found in the lo- ©
cality where the disease occurs.
“‘s, That the virus of spotted fever is very inti-
mately associated with the tissues of the tick’s body as
is shown by the fact that the female passes the infection
on to her young through her eggs, and further, by the
observation that in either of the two earlier stages of
the life cycle the disease may be contracted by biting
a sick animal and communicated to other animals
after molting or even after passing through an inter-
mediate stage.”
Professor R. A. Cooley of Montana, from whose
report the above quotation is taken, has also made
studies of the habits of the tick and believes there
can be no doubt that it is the disseminator of the
disease.
Relapsing Fever. The relapsing fever is an in-
fectious disease or possibly a group of closely re-
34 Insects and Disease
lated infectious diseases occurring in various parts
of the world. Occasionally it is introduced into
America, but it does not seem to spread here. It
has been shown that the disease is communicated
from one person to another by means of blood-
sucking insects. In Central Africa where the
disease is very prevalent a certain common tick
(Ornithodoros moubata) (Fig. 18) is known to
. transmit the disease. This tick lives in the resting
places and around the huts of the natives and has
habits very similar to the bedbug of other climes,
feeding at night and hiding during the day.
It attacks both man and beast and is one of the
most dreaded of all the African pests.
Nathan Bank, our foremost authority on ticks,
in summing up the evidence against them says:
“Tt is therefore evident that all ticks are potentially
dangerous. Any tick now commonly infesting some
wild animal, may, as its natural host becomes more
uncommon, attach itself to some domestic animal.
Since most of the hosts of ticks have some blood-
parasites, the ticks by changing the host may trans-
plant the blood-parasites into the new host producing,
under suitable conditions, some disease. Numerous
investigators throughout the world are studying this
phase of tick-life, and many discoveries will doubtless
signalize the coming years.”
Ticks and Mites a5
MITES
The mites are closely related to the ticks, and al-
though none of them has yet been shown to be
responsible for the spread of any disease their
habits are such that it would be entirely possible
for some to transmit certain diseases from one
host to another, from animal to animal, from ani-
mal to man, or from man to man. A number of
these mites produce certain serious diseases among
various domestic animals and a few are responsi-
ble for certain diseases of men.
Face-mites. Living in the sweat-glands at the
roots of hairs and in diseased follicles in the skin
of man and some domestic animals are curious
little parasites that look as much like worms as
mites (Fig. 19). Such diseased follicles become
filled with fatty matter, the upper end becomes
hard and black and in man are known as black-
heads. If one of these blackheads is forced out and
the fatty substance dissolved with ether the mites
may be found in all stages of development. The
young have six legs, the adult eight. The body is
elongated and transversely wrinkled. In man
they are usually found about the nose and chin
and neck where they do no particular harm except
to mar the appearance of the host and to indicate
36 Insects and Disease
that his skin has not had the care it should have.
Very recently certain investigators have found that
the lepre bacilli are often closely associated with
these face mites and believe that they may possibly
aid in the dissemination of leprosy. It is also
thought that they may sometimes be the cause of
cancer, but as yet these theories have not been
proven by any conclusive experiment.
In dogs and cats these same or very similar
parasites cause great suffering. In bad cases the
hair falls out and the skin becomes scabby. |
Horses, cattle and sheep are also attacked. The
disease caused by these mites on domestic animals
is not usually considered curable except in its very
early stages when salves or ointments may help
some. :
Itch-mites. “‘As slow as the seven-years’ itch”
is an expression, the meaning of which many could
appreciate from personal experience, for it certainly
seemed to take no end of time to get rid of the itch
once it was contracted. Just why seven years
should have been set for the limit of the disease is
not clear, for if the little roundish mites that cause
the disease live for seven years on a host they are
not going to move out voluntarily even if their
seven-year lease has expired.
The minute whitish mites (Fig. 20) that cause
a ee =
beiceitiviivia
Fic. r8—-Ornithodorus moubata, the Tick that
Transmits Relapsing Fever. From Boyce’s
“Mosquito or Man.”
Itc. 1t9—-The follicle mite (Demodex follicu-
lorum). (After Murray.)
Fic. 20—Itch-mite (Sarcoptes scabiet). (After
Murray.)
Fic. 21—Harvest-mites or “‘jiggers.”” (Leptus irritaus
and L. americanus.) (After Riley.)
Ticks and Mites a7
this disgusting disease are barely visible to the
naked eye. ‘They are usually very sluggish but
become more active when warmed. They live in
burrows just beneath the outer layer of skin,
sometimes extending deeper and causing most
intense itching. As the female burrows, she lays
her eggs from which come the young mites that are
to spread the infection. Various sulphur ointments
and washes are used as remedies. Cleanliness will
prevent infection.
Closely related to the itch-mite of man (Sarco ples
scabiet) are several kinds attacking domestic ani-
mals, causing mange, scab, etc. ‘The variety infest-
ing horses burrows in the skin and produces sores
and scabs, and is a source of very great annoyance.
These mites may also migrate to man. ‘Tobacco
water and sulphur ointments are used as remedies.
Horses and cattle are also infested by other
mites (Psoroptes communis) which cause the com-
mon mange. These do not burrow into the skin
but live outside in colonies, feeding on the skin and
causing crusts or scabs. ‘The inflammation causes
the animal to scratch and rub constantly and often
causes the loss of much of the hair.
Harvest-mites. A score or more of different va-
rieties of mites cause many other diseases of do-
mestic animals, such as the scab of sheep and hogs
38 Insects and Disease
and chickens, various other manges of the horses
and cattle and dogs, etc. But we need to call atten-
tion to just one more example, that of the harvest-
mites or jiggers (Fig. 21). Professor Otto Lugger,
from whose report on the Parasites of Man and
Domestic Animals most of these notes in regard to
the mites are taken, thus feelingly refers to this pest.
‘About the very worst pests of man and domesti-
cated animals are the Harvest-bugs, Red-bugs or Jig-
gers. . . . Men and animals passing through low herb-
age that harbors them are attacked by these pests, which,
whenever they succeed in finding a host, burrow in and
under the skin, causing intolerable itching and sores, the
latter caused by the feverish activity of the finger-nails
of the host, if that should be a man, whose energy in
scratching, apparently, cannot be controlled and who is
bound forcibly to remove the intruders. The writer
has been there! ‘Those who have ever passed through
meadows infested with red-bugs will remember the oc-
casion.”’
Horses, cattle, dogs and cats and other animals
suffer also. Again sulphur ointments are the best
remedies.
“The normal food of these mites must, apparently,
consist of the juices of plants, and the love of blood
proves ruinous to those individuals which get a chance
Ticks and Mites 39
to indulge it. For, unlike the true chigoe, the female
of which deposits eggs in the wound she makes, these
harvest-mites have no object of the kind, and when
not killed at the hands of those they torment they soon
die victims to their sanguinary appetite.”
CHAPTER IV
HOW INSECTS CAUSE OR CARRY
DISEASE
Ky We has been estimated that there are
bea i about four thousand species or kinds of
OB! Prot bout twenty-five thou-
Siw Gix| Protozoans, about twenty-five thou
sand species of Mollusks, about ten
thousand species of birds, about three thousand
five hundred species of mammals, and from two
hundred thousand to one million species of insects,
or from two to five times as many kinds of insects
as all other animals combined.
Not only do the insects preponderate in number
of species, but the number of individuals belonging
to many of the species is absolutely beyond our
comprehension. ‘Try to count the number of little
green aphis on a single infested rose-bush, or on a
cabbage plant; guess at the number of mosquitoes
issuing each day from a good breeding-pond; es-
timate the number of scale insects on a single
square inch of a tree badly infested with San José
scale; then try to think how many more bushes or
40
of.
How Insects Cause or Carry Disease 41
trees or ponds may be breeding their millions just
as these and you will only begin to comprehend the
meaning of this statement.
As long as these myriads of insects keep in what
we are pleased to call their proper place we care
not for their numbers and think little of them ex-
cept as some student points out some wonderful
thing about their structure, life-history or adapta-
tions. But since the dawn of history we find ac-
counts to show that insects have not always kept
to their proper sphere but have insisted at various
times and in various ways in interfering with man’s
plans and wishes, and on account of their exces-
sive numbers the results have often been most dis-
astrous. :
Insects cause an annual loss to the people of the
United States of over $1,000,000,000. Grain fields
are devastated ; orchards and gardens are destroyed
or seriously affected; forests are made waste places
and in scores of other ways these little pests which
do not keep in their proper places are exacting this
tremendous tax from our people.
These things have been known and recognized
for centuries, and scores of volumes have been
written about the insects and their ways and of
methods of combating them.
But it is only in recent years that we have begun
42 Insects and Disease |
to realize the really important part that insects
play in relation to the health of the people with
whom they are associated. Dr. Howard estimates
that the annual death rate in the United States
from malaria is about twelve thousand, entailing
an annual monetary loss of about $100,000,000, to
say nothing of the suffering and misery endured by
the afflicted. All this on account of two or three
species of insects belonging to the mosquito genus
Anopheles.
Yellow fever, while not so wide-spread, is more
fatal and therefore more terrorizing. Its presence
and spread are due entirely to a single species of
mosquito. Flies, fleas, bedbugs, and many other
insects have been shown to be intimately connected
with the spread of several other most dreaded
diseases, so it is no wonder that physicians, ento-
mologists and biologists are studying with utmost
zeal many of these forms that bear such a close
relation not only to our welfare and comfort but
to our lives as well.
It would be out of place to try to give here even a
brief outline of the classification of insects, such as
may be found in almost any of the many books
devoted to their study.
The most generally accepted classification di-
vides the insects into nineteen orders; as the
How Insects Cause or Carry Disease 43
Coleoptera, containing the beetles; the Lepidop-
tera, containing the butterflies and moths; the Hy-
menoptera containing the bees, ants and wasps,
etc. Four or five of these orders will be of more or
less interest to us.
The order Diptera, or two-winged flies, is the
most important because to this belong the mos-
quitoes which transmit malaria and yellow fever,
and the house-fly that has come into prominence
since it has been found to be such an important
factor in the distribution of typhoid and other
diseases.
FLIES
The order Diptera is divided into sixty or more
families, many of which contain species of con-
siderable economic importance. For our present
consideration the flies may be divided into two
groups or sections: those with their mouth-parts
fitted for piercing such as the mosquito and horse-
fly, and those with sucking mouth-parts such as the
house-fly, blow-fly and others.
Some of the species belonging to the first group
are among the most troublesome pests not only of
man but of our domestic animals as well. Next
to the mosquitoes the horse-flies (Fig. 22) are per-
haps the best known of these. There are several
species known under various names, such as gad-
44 Insects and Disease
fly, breeze-fly, etc. They are very serious pests of
horses and cattle, sometimes also attacking man.
Their strong, sharp, piercing stylets enable them to
pierce through the toughest skin of animals and
through the thin clothing of man. The bite is very
severe and irritating, and as the flies sometimes
occur in great numbers the annoyance that they
cause is often very great indeed. It has often been
claimed that these flies as well as the stable-fly and
others carry the anthrax bacillus on their proboscis
from one animal to another, and although this may
not have been definitely proven the evidence is
strong enough to make a very good case against the
accused. It is interesting to note in this connection
that anthrax, a very common disease among the
domestic animals and one which may attack man
also, was the first disease to be shown to be of
bacterial origin. It was only about thirty-five
years ago that the investigations of Koch and
Pasteur demonstrated that the presence of this
particular germ (Bacillus anthracis) was the cause
of the disease, and it was early recognized that such
biting flies may be important factors in the spread
of the disease.
The stable-fly (Fig. 23) (Stomoxys calcitrans)
which looks very much like the house-fly and, as
will be noted later, frequently enters houses, is
Itc. 22—Horse-fly (Tabanus
punctifer). x 1%.
Fic. 23—Stable-fly (Stomoxys calcitrans). x 4%.
Fic. 26
Fic. 24—A Black-fly (Simulium sp.). (From Kellogg’s Amer.
Insects.)
Fic. 25—Screw-worm fly (Chrysomyia macellaria).
Fic. 26—Blow-fly (Calliphora vomitoria).
How Insects Cause or Carry Disease 45
often an important pest of horses and cattle. Its
blood-sucking habit makes it quite possible that
it too may be concerned in carrying anthrax and
other diseases. |
In a later chapter it will be shown how the tse-
tse-fly, which is somewhat like the stable-fly, is
_ responsible for the spread of the disease known
as the sleeping sickness. ‘This disease is caused
by a Protozoan parasite, a trypanosome, which is
transmitted from one host to another by the tse-
beay°
In Southern Asia and in parts of Africa there is a
very serious disease of horses known as surra which
is caused by a similar parasite (Trypanosoma
evanst). ‘This parasite attacks horses, mules,
camels, elephants, buffaloes and dogs, and has been
recently imported into the Philippines. It is sup-
posed that flies belonging to the same genus as the
horse-fly (Tabanus and others), and the stable-fly
(Stomoxys) and the horn-fly (Hematobia) are re-
sponsible for the spread of the disease.
Nagana is one of the most serious diseases of
domestic animals in Central and Southern Africa.
In some sections it is almost impossible to keep any
kind of imported animals on account of this disease
which is caused by a parasite (Trypanosoma
brucer) similar to the one causing surra. ‘This
46 Insects and Disease
parasite is to be found in several different kinds of
native animals which seem to be practically im-
mune but are always a source of danger when other
animals are introduced. ‘Two or three species of
tsetse-flies are responsible for the transmission of
this disease.
Another group of flies much smaller but more
numerous and much more insistent are the black-
flies or buffalo-gnats (Fig. 24). For more than a
century these little flies have been recognized as
among the most serious pests of stock, particularly
in the south where, besides the actual loss by death
of many animals yearly, the annoyance is so great
as to sometimes make it impossible to work in the
field. Human beings are often attacked, and as
the bite is poisonous and very painful great suffer-
ing may result and cases of deaths from such
bites have been reported.
Belonging to another family, and smaller, but
much like the buffalo-gnat in habits, are the minute
little ‘‘punkies” or ‘‘no-see-ums”’ which sometimes
occur in great swarms in certain regions where
they make life a burden to man and beast. While
it has not been shown that either the buffalo-gnats
or the punkies are responsible for the transmission
of any disease, their habits of feeding on so many
different kinds of wild and domestic animals as
How Insects Cause or Carry Disease 47
well as on man makes it possible for them to act
as carriers of parasites that might under proper
conditions become of serious importance. ‘Then,
too, the irritation caused by the bites of these in-
sects usually causes scratching which may result
in abrasions of the skin that open the way for
various harmful germs, particularly those causing
skin diseases.
Coming now to the group containing the house-
flies and related forms we find a number that are
of interest on account of the suffering that they
may cause, particularly in their larval stages.
The screw-worm flies (Chrysomyia macellaria)
are among the most common and important of
these (Fig. 25). ‘These ‘‘gray flies,” as they are
sometimes called, lay a mass of three or four
hundred eggs on the surface of wounds. The
larvee which in a few hours hatch from these make
their way directly into the wound where they feed
on the surrounding tissue until full grown when
they wriggle out and drop to the ground where
they transform to the pupa and later to the adult
fly. Of course their presence in the wounds is
very distressing to the infected animal, and great
suffering results. Slight scratches that might other-
wise quickly heal often become serious sores be-
cause of the presence of these larve.
48 Insects and Disease
Many cases are recorded of these flies laying
their eggs in the ears or nose of children or of per-
sons sleeping out of doors during the day. Espe-
cially is this apt to occur if there are offensive dis-
charges which attract the fly. In such cases the
larvee burrow into the surrounding tissues, de-
vouring the mucous membranes, the muscles and
even the bones, causing terrible suffering and
usually, death. The larve in such situations may
be killed with chloroform and, if the case is at-
tended to before they have destroyed too much of
the tissues, recovery usually occurs.
The blow-flies (Fig. 26) (Calliphora vomitoria)
and the bluebottle flies (Fig. 27), (Lucila spp.)
and the flesh-flies (Fig. 28) (Sarcophaga spp.) all
have habits somewhat like the screw-worm fly.
Any of them may lay their eggs in wounds on man
or animals with the same serious results.
The flesh-fly instead of laying eggs deposits the
living larve upon meat wherever it is accessible,
and as these develop with astonishing rapidity they
are able to consume large quantities of flesh in a
remarkably short time. In this way they may be
of some importance as scavengers, but it is better
to get rid of the waste in other ways than to leave
it for a breeding-place for flies that are capable of
causing so much damage and suffering.
How Insects Cause or Carry Disease 49
Not infrequently the larve of certain flies are
to be found in the alimentary canal where as a rule
they do no particular damage. Altogether the
larvee of over twenty different species of flies have
been found in or expelled from the human in-
testinal canal. In Europe, the majority of these
larve belong to a fly which looks very much like
the house-fly except that it is somewhat smaller
and so is often known as “‘the little house-fly”
(Fig. 29) (Homalomyia canicularis). The same
species is very common in the United States, fre-_
quently occurring in houses. Under certain con-
ditions it may even be more abundant than the
house-fly. It is believed that the larve in the in-
testinal canal come from eggs that have been de-
posited on the victim while using an outdoor privy
where the flies are often very abundant. Instances
are also on record where these larve have been
discharged from the urethra.
Another fly (Ochromyia anthropophaga) occur-
ring in the Congo region has a blood-sucking larvee
which is known as the Congo floor-maggot. The
fly which is itself not troublesome deposits its eggs
in the cracks and crevices of the mud floors of the
huts. The larve which hatch from these crawl out
at night and suck the blood of the victim that may
be sleeping on the floor or on a low bed.
50 Insects and Disease
BOT-FLIES
Another group of flies known as the bot-flies
(Fig. 30) have their mouth-parts rudimentary or
entirely wanting so of course they themselves can-
not bite or pierce an animal. Nevertheless they
are the source of an endless amount of trouble to
stockmen and sometimes even attack man. Al-
though these flies cannot bite, the presence of even
a single individual may be enough to annoy a horse
almost to the end of endurance. Horses seem to
have an instinctive fear of them and will do all in
their power to get rid of the annoying pests.
The eggs of the house bot-fly are laid on the
hair of the legs or some other part of the body.
The horse licks them off and they hatch and
develop in the alimentary canal of their host.
Sometimes the walls of the stomach may be
almost covered with them thus of course seriously
interfering with the functions of this organ. When
full grown the larve pass from the host and com-
plete their transformation in the ground.
The bot-flies of cattle or the oxwarbles (Fig. 31).
gain an entrance into the alimentary canal in the
same way, that is, by the eggs being licked from the
hairs on the body where they have been laid by
the adult fly. But instead of passing on into the
Fic. 27—Bluebottle fly (Lucilia sericata).
Fic. 28—Flesh-fly (Sarcophaga sp).
Fic. 29—‘‘ The little house-fly”
(Homalomyia canicularis).
Fic. 30—Horse bot-fly (Gastrophilus
equt).
Fic. 31—Ox warble-fly (Hypoderma Fic. 32—Sheep bot-fly (Gastrophilus
lineata). nasalis).
How Insects Cause or Carry Disease 51
stomach they collect in the esophagus and later
make their way through the walls of this organ and
through the tissues of the body until they at last
reach a place along the back just under the skin.
Here as they are completing their development
they make more or less serious sores on the backs
of the infested animals. The hides on such ani-
mals are rendered nearly valueless by the holes
made by the larvee. When fully mature they drop
to the ground and complete their transformations.
The sheep bot-flies (Fig. 32) lay their eggs in
the nostrils of sheep. The larve pass up into the
frontal sinuses where they feed on the mucus,
causing great suffering and loss. Many other
species of animals are infested with their own par-
ticular species of bots. Several instances are
recorded where the oxwarble has occurred in man,
always causing much suffering and sometimes
death.
One or more species of bot-flies occurring in the
tropical parts of America frequently attack man.
The early larval stage soon after it has entered the
skin is known as the Ver macaque. Later stages
as torcel or Berne. ‘The presence of the larve pro-
duces very painful and troublesome sores. It is
supposed that the adult flies (one species of which
is Dermatobia cyaniveniris) lay their eggs on the
52 Insects and Disease
skin which the larve penetrate as soon as they
hatch. It has also been suggested that they might
reach the subcutaneous tissue by migrating from
the alimentary canal as do some of the other bot-
flies. A very serious eye disease, Egyptian opthal-
mia, is known to be spread by the house-flies and
others. These flies are often abundant about the
eyes, especially of children suffering from this
disease. It is suspected that certain small flies
(Oscinide) in the southern part of the United
States are responsible for the spread of disease
known as “‘sore eye.”’
FLEAS
The fleas used to be considered as degenerate
Diptera and were placed with that group but they
are now classed as a separate order (Siphonaptera).
Within recent years these little pests have come
into special prominence on account of their im-
portance in connection with the spread of the
plague. The fact that they are so abundant every-
where and that they will so readily pass from one
host to another makes the possibility of their
spreading infectious diseases very great. Besides
the kinds that are concerned in the transmission
of plague, which are discussed in another chap-
ter, there are many other kinds infesting various
How Insects Cause or Carry Disease 53
wild and domesticated animals and a few attack-
ing birds.
One of the most important of these is the jigger-
flea or chigoe (Dermatophilus penetrans, Fig. 33).
Various other names such as chigger-flea, sand-
flea, jigger, chigger are also applied to this insect
as well as to a minute red mite that burrows into
the skin in much the same way as the female of
the flea. So although they are entirely different
creatures you can never tell from the common
name, whether it is the flea or the mite that is be-
ing referred to. Both the male and female jigger-
fleas feed on the host and hop on or off as do other
fleas, but when the female is ready to lay eggs
(Fig. 34), she burrows into the skin. Her pres-
ence there causes a swelling and usually an ulcer
which often becomes very serious, especially if the
insect should be crushed and the contents of the
body escape into the surrounding tissue.
These little pests are found throughout tropical
and subtropical America and have been introduced
into Africa and from there have spread to India
and elsewhere. ‘They attack almost all kinds of
animals as well as many birds, being of course a
source of great annoyance and no inconsiderable
loss. They are more apt to attack the feet of men,
especially those who go barefooted. Sometimes
54. Insects and Disease
they occur in such numbers as to make great
masses of sores.
On account of being such general feeders they
are difficult to control, but some relief may be ob-
tained by keeping the houses and barns as free as
possible from dirt and rubbish and by sprinkling
the breeding-places of the pest with pyrethrum
powder or carbolic water. ‘Those that gain an en-
trance into the skin should be cut out, care being
taken to remove the insect entire.
BEDBUGS
In the order Hemiptera, or the true ‘‘bugs” in
an entomological sense, we find a few forms that
may carry disease. ‘The bedbug (Fig. 35) (Camex
lectularis) has been accused of transmitting plague,
relapsing fever and other diseases. Very recent
investigations show that the common bedbug of
India (Cimex rotundaius) harbors the parasite
that causes the disease known as kala azar, and
there is no doubt that it transmits the disease.
LICE
The sucking lice (Fig. 36) which also belong to
this order are suspected of carrying some of these
same diseases. It is thought that the common
male (Dermato ph-
flea,
Fic. 33—Chigo or jigger
Karsten.)
(After
ilus penetrans).
female distended with eggs.
(After
2
Fic. 34—Chigo
Karsten.)
Fic. 36—Body-louse (Pediculus vestimen't),
(From drawing by: J. H. Pain:.;
How Insects Cause or Carry Disease 55
louse on rats (He@matopinus spinulosus) is respon-
sible for the spread from rat to rat of a certain
parasite. (Trypanosoma lewist), which, however,
does not produce any disease in the rats, but if
they are capable of acting as alternative hosts
for such parasites, it is quite possible that they
may also carry disease-producing forms.
HOW INSECTS MAY CARRY DISEASE GERMS
Insects may carry the germs or parasites which
cause disease in a purely mechanical or accidental
way, that is, the insect may in the course of its
wanderings or its feeding get some of the germs on
or in its body and may by chance carry these to
the food, or water, or directly to some person who
may become infected. ‘Thus the house-fly may
carry the typhoid germs on its feet or in its body
and distribute them in places where they may enter
the human body.
Several other flies as well as fleas, bedbugs.
ticks, etc., may also carry disease germs in this
mechanical way. While this method of transmis-
sion is just as dangerous as any other, and possi-
bly more dangerous because more common, an-
other method in which the insect is much more
intimately concerned is more interesting from a
biological standpoint at least and will be discussed
56 Insects and Disease
more fully in the chapters on malaria, yellow fever
and elephantiasis.
In these cases the insect is one of the necessary
hosts of the parasite, which cannot go on with its
development or pass from one patient to another
unless it first enters the insect at a certain stage of
its life-history.
ee aire
si
;
Ie:
lest
Uitte?
22 ECLECTIC. SERIES.
LESSON Vil,
spl’ ders tickling
stay néck
nose se’eret
erawls loos
beck Ope
foes toes
speck . chdogse
dot ~< nod
shocs spread be lieve’ gi
BABY-BYE. eC
1. Baby-Bve,
Here's ,a fly;
We will watch him, you and I.
How he crawls
Up the walls,
Yet he never falls!
T believe with six such legs.
You and I could walk on eggs,
There he goes a7
On his toes,
Tickling Baby’s nose.
Fic. 37—One use for the house-fly.
CHAPTER V
HOUSE-FLIES OR TYPHOID-FLIES
7 a; HE page shown in Fig. 37 was copied from
wie Re<4| one of our old second readers and shows
hie | JM something of the spirit in which we used
to regard the house-fly. A few of them
were nice things to have around to make things
seem “‘homelike.”” Of course they sometimes be-
came too friendly during the early morning hours
when we were trying to take just one more little nap
or they were sometimes too insistent for their por-
tion of the dinner after it had been placed on the
table, but a screen over the bed would help us out
a little in the morning and a long fly-brush cut
from a tree in the yard or made of strips of paper
tacked to a stick or, still more fancy, made of long
peacock plumes, would help to drive them from
the table. Those that were knocked into the coffee
or the cream could be fished out; those that went
into the soup or the hash were never missed!
Not only were the flies regarded as splendid
things with which to amuse the baby, but they
57
58 _ Insects and Disease
were thought to be very useful as scavengers as
they were often seen feeding on all kinds of refuse
in the yard. ‘Then, too, they seemed to be cleanly
little things, for almost any time some of them
could be seen brushing their heads and bodies
with their legs and evidently having a good
clean-up. More than that it never occurred to
us that it would be possible to get rid of them
even should it be thought advisable, for they came
from ‘“‘out doors,” and who could kill all the flies
“out doors” ?
Fortunately, or otherwise, these halcyon days
have gone by and the common, innocent, friendly
little house-fly is now an outcast convicted of
many crimes and accused of a long list of others
(Fig. 38).
Its former friends have become its sworn ene-
mies. ‘The foremost entomologist of the land has
suggested that we even change its name and give
it one that would be more suggestive of the ab-
horence with which we now look upon it.
And all these changes have come about because
science has turned the microscope on the house-
fly and men have studied its habits. We know
now that as the fly is “tickling baby’s nose”’ it
may be spreading there where they may be in-
haled or where they may be taken into the baby’s
Fic. 38—The house-fly (Musca domestica).
House-Flies or Typhoid-Flies 59
mouth thousands of germs some of which may
cause some serious disease. We know that as
they are buzzing about our faces while we are
trying to sleep they may, unwittingly, be in the
same nefarious business, and we know that as they
sip from our cups with us or bathe in our coffee
or our soup or walk daintily over our beefsteak
or frosted cake they are leaving behind a trail of
filth and bacteria, and we know that some of these
germs may be and often are the cause of some of
our common diseases. As the typhoid germs are
very often distributed in this way, Dr. Howard
has suggested that the house-fly shall be known
in the future as the typhoid-fly, not because it is
solely responsible for the spread of typhoid, but
because it is such an important factor in it and
is so dangerous from every point of view. The
names ‘‘manure fly” and “‘privy fly” have also
been suggested and would perhaps serve just as
well, as the only object in giving it another name
would be to find a more repulsive one to remind
us constantly of the filthy and dangerous habits
of the fly.
STRUCTURE
In order that we may better understand why
it is that the house-fly is capable of so much
mischief, let us consider briefly a iew points in
60 Insects and Disease
regard to its structure, its methods of feeding and
its life-history. 3
The large compound eyes are the most con-
spicuous part of the head (Fig. 39). In front,
between the eyes, are the three-jointed antenne,
the last joint bearing a short, feathery bristle.
From the under side of the head arises the long,
fleshy proboscis (Fig. 40). When this is fully
extended it is somewhat longer than the head;
when not distended and in use it is doubled back
in the cavity on the under side of the head. About
half-way between the base and the middle is a
pair of unjointed mouth-feelers (maxillary palpi).
At the tip are two membranous lobes (Fig. 41)
closely united along their middle line. These are
covered with many fine corrugated ridges, which
under the microscope look like fine spirals and
are known as pseudotrachee. ‘Thus it will be seen
that the house-fly’s mouth-parts are fitted for suck-
ing and not for biting. Its food must be in a
liquid or semi-liquid state before it can be sucked
through the tube leading from the lobes at the tip
up through the proboscis and on into the stomach.
If the fly wishes to feed on any substance such as
sugar, that is not liquid, it first pours out some ~
saliva on it and then begins to rasp it with the
rough terminal lobes of the proboscis, thus re-
Fic. 39-—Head of house-fly showing
eyes, antennie and mouth-parts.
Fic. 4o—Proboscis of house-
fly, side view.
Fic. 41—Lobes at end of proboscis of house-fly showing corru-
gated ridges.
Fic. 42—Wing of house-fly.
House-F te or Typhoid-Flies 61
ducing the food to a consistency that will enable
the fly to suck it up. Many people think that
house-flies can bite and will tell you that they
have been bitten by them. Buta careful examina-
tion of the offender, in such instances, will show
that it was not a house-fly but probably a
_ Stable-fly, which does have mouth-parts fitted for
piercing.
The thorax bears the two rather broad, mem-
branous wings (Fig. 42) which have characteristic
venation. ‘Three of these veins end rather close
together just before the tip of the wing, the pos-
terior one of the group being bent forward rather
sharply a short distance from the tip. The stable-
fly has this vein slightly curved forward but not
nearly so conspicuously (Fig. 43).
Nearly all the other flies that are apt to be mis-
taken for the house-fly do not have this vein
curved forward. The wings, although apparently
bare, are covered with a fine microscopic pubes-
cence. Among these fine hairson the wing as well
as among similar fine ones and coarser ones all
over the body, particles of dust and dirt or filth
(Fig. 44) or, what interests us more just now,
thousands of germs may find a temporary lodg-
ment and later be scattered through the air as the
insect flies. Or they may get on our food as the
62 Insects and Disease
fly feeds or while it rests and combs its body with
the rows of coarse hairs on its legs.
“The legs are rather thickly covered with coarse
hairs or bristles and with a mat of fine, short
hairs. On some of the segments the larger hairs
are arranged in rows and are used as a sort of
comb with which the fly combs the dirt from the
rest of its body. The last segment (Fig. 45) of
the leg bears at its tip a pair of large curved claws
and a pair of membranous pads known as the
pulvillz. On the under side of the pulville are
innumerable minute secreting hairs (Fig. 46) by
means of which the fly is able to walk on the wall
or ceiling or in any position on highly-polished
surfaces.
HOW THEY CARRY BACTERIA
These same little pads, with their covering of
secreting hairs, are perhaps the most dangerous
part of the insect for they cannot help but carry
much of the filth over or through which the fly
walks, and as this may be well stocked with germs
the danger is at once apparent.
As the result of a series of carefully planned
experiments it has been demonstrated that the
number of bacteria on a single fly may range all
the way from 550 to 6,600,000 with an average for
the lot experimented with of about one and one-
Fic. 43—Wing of Stable-fly (Slomoxy;s calcitrans).
Fic. 44—Wing of house-fly showing particles of dirt adher-
ing to it.
Fic. 45—Last three segments of leg of house-fly showing the
claws, the pulvillz and the hairs on the legs.
Fig. 46—Foot of house-fly showing claws, hairs, pul-
ville and the minute clinging hairs on the pulville.
Fic. 47—Larva of house-fly.
House-Flies or Typhoid-Flies 63
fourth million bacteria to each fly. Now where
do all these bacteria come from? Necessarily
from the place where the fly breeds or where
it feeds.
LIFE-HISTORY AND HABITS
The eggs of the house-fly may be laid on almost
any kind of decaying or fermenting material. If
this is kept moist and a proper temperature main-
tained the larve or maggots (Fig. 47) that hatch
from the eggs may develop. As a rule, however,
these requirements are found only under certain
conditions and are ordinarily found only in ma-
nure heaps or in privy vaults or latrines. All ob-
servers agree that the female fly prefers to deposit
her eggs in horse manure when this can be found
and when this is piled in heaps in the barn-yard
(Fig. 48) or in the field the heat caused by the
decay and fermentation makes ideal conditions
for the development of the larve. Cow manure
may serve as a breeding-place to a limited extent.
The flies are immediately attracted to human ex-
crement and breed freely in it when opportunity
offers. Decaying vegetables or fruit, fermenting
kitchen refuse and other materials sometimes also
‘serve as. breeding-places.
In suitable places in warm weather the eggs will
64 Insects and Disease
hatch in from eight to twelve hours and the larvee
will become fully developed in from eight to four-
teen days. They then change to pupe (Fig. 50)
in which stage they may remain for another eight
to twenty days when the adult flies will emerge.
These figures must necessarily be indefinite be-
cause the weather and other conditions always
vary. Under the most favorable conditions of
moisture and temperature it is probably never less
than eight days from egg to adult fly and under
unfavorable conditions it may be as long as six
weeks.
The larvee thrive best when the manure is kept
quite wet. I have often found them in almost
incredible numbers in stables that had not been
cleaned for some time. The horses standing there
at night added fresh material and kept it just wet
enough to make conditions almost ideal (Fig. 49).
The pupz are usually found where the manure
is a little dryer, but it must not be too dry. When
the flies issue from the pup they push their way
up to the surface where they remain for a short
time and allow the body to harden and the wings
to dry before they fly away to other manure or, —
as too often happens, to some near-by kitchen or
restaurant or market place.
Of course it is impossible for them to issue from
‘sasnoy Aq-1vaU
94} [[B SUTjSajU pue say BUIPseIq 19M SaIy Jo SUON[IY ‘sInueW YIM pal]y pred-uieg—sgh “O17
"s}0338 ul
YJIA peiaAoo sem OOH 94} pue skep sUIOS 10 paAoUaI UVeq JOU peY sInuUeUT IY} ‘S{[eIS AWIG—O6b “O17
House-Flies or Typhoid-Flies 65
this filth without more or less of it clinging to their
bodies. Now if these flies would breed only in
barn-yard manure and fly directly from the stable
to the house there would be comparatively little
reason to complain, at least from a sanitary stand-
point, for the amount of barn-yard filth that they
carried to our food would be of little consequence.
But when they breed in privy vaults or similar
places, or visit such places before coming into the
house or dairy or market place the results may be
much more serious.
FLIES AND TYPHOID
It has been abundantly demonstrated that the ex-
crement or the urine of a typhoid patient may con-
tain virulent germs for some time before he is aware
that he has the disease, and it has been shown that
the germs may be present for weeks or months,
and in some cases even years after the patient has
recovered. If a fly breeds in such infected ma-
terial, or feeds or walks on it, it is very apt to get
some of the germs on its body where they may re-
tain their virulence for some time, and should it
visit our food while covered with these germs some
of them would probably be left there where they
might produce serious results. More than that. If
the fly should feed on such infected material the
66 Insects and Disease
typhoid germs would go on developing in the in-
testine of the fly and would be passed out with the
feces in which they retain their virulence for some
days. In other words, the too familiar ‘‘fly-specks”’
are not only disgusting, but may be a very grave
source of danger. It will be seen that in this way
several members of a community might become
infected with the typhoid germs before anyone was
aware that there was a case of typhoid or a ‘‘bacil-
lus carrier’’ in the neighborhood.
One more example out of the scores that might
be cited to show how the fly may carry typhoid
germs. ‘They may enter the sick chamber in the
home or in the hospital and there gain access to the
typhoid germs. ‘These they may carry to other
parts of the house or to near-by houses, or the flies
may light on passing carriages or cars and be
carried perhaps for miles before they enter another
house and contaminate the food there.
These are hypothetical cases, but they illustrate
what is taking place hundreds of times every season
all over the world wherever typhoid fever and flies
occur, and no country or race is known to be im-
mune from typhoid, and the fly is found ‘‘ wherever
man is found.” |
In the summer of 1898 a commission was ap-
pointed to investigate the prevalence of typhoid
House-Flies or Typhoid-Flies 67
fever in the United States Army Concentration
Camps. The following are some of the conclusions
as reported by Dr. Vaughan:
‘““FLIES UNDOUBTEDLY SERVED AS CARRIERS OF THE
INFECTION
“My reasons for believing that flies were active in
the dissemination of typhoid may be stated as follows:
‘qa, Flies swarmed over infected fecal matter in the
pits and then visited and fed upon the food prepared
for the soldiers at the mess tents. In some instances
where lime had recently been sprinkled over the con-
tents of the pits, flies with their feet whitened with
lime were seen walking over the food.
‘‘b, Officers whose mess tents were protected by means
of screens suffered proportionately less from typhoid
fever than did those whose tents were not so protected.
“‘¢, Typhoid fever gradually disappeared in the fall
of 1898, with the approach of cold weather, and the
consequent disabling of the fly.
“Tt is possible for the fly to carry the typhoid bacil-
lus in two ways. In the first place, fecal matter con-
taining the typhoid germ may adhere to the fly and be
mechanically transported. In the second place, it is
possible that the typhoid bacillus may be carried in the
digestive organs of the fly and may be deposited with
its excrement.”
In Dr. Daniel D. Jackson’s report to the Mer-
chants’ Association of New York on the “‘ Pollution
68 Insects and Disease
of New York Harbor asa Menace to the Health by
the Dissemination of Intestinal Diseases Through
the Agency of the Common House-fly,” he shows
graphically that the prevalence of typhoid and
other intestinal diseases is coincident with the
prevalence of flies, and that the greatest number
of deaths from such diseases occurs near the river
front where the open or poorly constructed sewers
scatter the filth where the flies can feed on it, or
along the wharves with their inadequate accom-
modations and the resulting accumulation of
filth.
FLIES AND OTHER DISEASES
Not only is the house-fly an important factor in
the dissemination of typhoid fever, but it has been
definitely shown that it is capable of transmitting
several other serious diseases. |
The evidence that flies carry and spread the
deadly germs of cholera is most conclusive. The
germs may be carried on the body where they will
live but a short time, or they may be carried in the
alimentary canal where they will live for a much
longer period and are finally deposited in the fly-
specks where they retain their virulence for some
time. Flies that had been allowed to contaminate
themselves with cholera germs were allowed ac-
cess to milk and meat. In both cases hundreds of
House-Flies or Typhoid-Flies 69
colonies of the germs could later be recovered from
the food. As with the typhoid germs milk seems to
be a particularly good medium for the develop-
ment of the cholera germs. In several of the ex-
periments that have been made along this line the
milk has been readily infected by the flies visiting it.
Of course an outbreak of cholera is of rare
occurrence in our country, but unfortunately this
is not so in regard to some other intestinal diseases
such as diarrhea and enteritis which annually
cause the death of many children, especially bottle-
fed babies. Those who have made close studies of
the way in which these diseases are disseminated
are convinced that the flies are one of the most
- important factors in their spread.
It has long been observed that flies are par-
ticularly fond of sputum and will feed on it on the
sidewalk, in the gutter, the cuspidor or wherever
opportunity offers. It is well known, too, that
the sputum of a consumptive contains myriads
of virulent tubercular germs. A fly feeding and
crawling over such material must necessarily get
some of it on its body, and as it dries and the insect
flies about the germs will be distributed through
the air, possibly over our food. It has been shown
that the excretion from a fly that has fed on tuber-
cular sputum contains tubercular bacilli that may
70 Insects and Disease
remain virulent for at least fifteen days. Thus we
see again the danger that may lurk in the too
familiar ‘‘fly-specks.”’
Although it is generally supposed that the flea is
solely responsible for the spread of the bubonic
plague and no doubt is the principal distributing
agent, the fact must not be overlooked that the
house-fly may also be of considerable importance
in this connection. Carefully planned experiments
have shown that flies that have become infected by
being fed on plague-infected material may carry
the germs for several days and that they may die
of the disease. During plague epidemics flies may
become infected by visiting the sores on human or
rat victims or by feeding on dead rats or on the ex-
creta of sick patients, and an infected fly is always a
menace should it visit our food or open wounds or
sores. Anthrax bacilli are carried about and
deposited by flies showing the possibility of the
disease being spread in this way.
Some believe that leprosy, smallpox and many
other diseases are carried by the house-fly, so it is
little wonder that it is fast losing its standing as a
household companion and that we are beginning to
regard it not only as a nuisance but as a source of
danger which should no longer be tolerated in any
community.
House-Flies or Typhoid-Flies 71
Of course only a small per cent of the flies that
visit our food in the dairies or market places or
kitchens actually carry dangerous diseases, but they
are all bred in filth and it is not possible without
careful experiments or laboratory analysis to de-
termine whether any of the germs among the mil-
lions that are on their bodies are dangerous or not.
The chances that they may be are too great. The
only safe way is to banish them all or to see that
all of our food is protected from them.
FIGHTING FLIES
Screens and sticky fly-paper have their places
and give some little relief in a well-kept house.
But of what use is it to protect your food after it
has entered your home if in the stores, in the
market place, in the dairy barn, or dairy wagon,
in the grocers’ and butchers’ cart, it has been ex-
posed to contamination by hundreds of flies that
have visited it.
The problem is a larger one than keeping the
house free from flies; larger but not more difficult,
for the remedy is simple, effective, practicable and
inexpensive. Destroy their breeding-places and
you will have no flies. As the flies breed prin-
cipally in manure the first remedial measure is to
see that all manure is removed from the barn-yard
72 Insects and Disease
at least once a week and spread over the fields
to dry, for the flies cannot breed in the dry ma-
nure. If it is not practicable to remove it this
often the manure should be kept in a bin that is
closed so tight that no flies can get into it to lay
their eggs. Sometimes the manure may be treated
with some substance such as kerosene, crude oil,
chlorid of lime, tobacco water or mixture of two
or more of these and thus rendered unsuitable for
the flies to breed in, but in general practice none
of them has been found very satisfactory for the
treatment is either not thorough enough or is too
expensive of time and material.
Outdoor privies and cesspools must be carefully
attended to. ‘The latter can be easily covered so no
flies can get in and if the filthy and in every way
dangerous pit under the privy be filled and the
dry-earth closet substituted one of the greatest
sources of danger; especially in the country and in
towns with inadequate sewerage facilities, will be
done away with. After these things are done there
remain only the garbage cans and the rubbish
heaps to look after.
Of course your neighbor must keep his place
clean too, for his flies are just as apt to come into
your house as his, so the problem becomes one for
the whole community.
House-F lies or Typhoid-Flies 73
Almost all cities and many of the smaller towns
have ordinances which if enforced would afford
adequate protection from flies, but they are sel-
dom if ever rigidly enforced and it yet remains
for some enterprising town to be able to advertise
itself as a “‘speckless town”’ as well as a ‘‘spotless
town.”
AN EXPERT’S OPINION
In a recent important bulletin issued by the
Bureau of Entomology, Dr. L. O. Howard dis-
cusses the economic importance of several of the
insects that carry disease. I wish to quote two or
three paragraphs from the pages in which he dis-
cusses the house-fly or typhoid fly to show the
opinion of this excellent authority in regard to this
pest.
‘Even if the typhoid or house fly were a creature
difficult to destroy, the general failure on the part of
communities to make any efforts whatever to reduce
its numbers could properly be termed criminal neg-
lect; but since, as will be shown, it is comparatively
an easy matter to do away with the plague of flies, this
neglect becomes an evidence of ignorance or of a care-
lessness in regard to disease-producing filth which to
the informed mind constitutes a serious blot on civi-
lized methods of life.”
On another page:
74 Insects and Disease
‘‘We have thus shown that the typhoid or house fly
is a general and common carrier of pathogenic bacteria.
It may carry typhoid fever, Asiatic cholera, dysentery,
cholera morbus, and other intestinal diseases; it may
carry the bacilli of tuberculosis and certain eye diseases.
It is the duty of every individual to guard so far as
possible against the occurrence of flies upon his prem-
ises. It is the duty of every community, through its
board of health, to spend money in the warfare against
this enemy of mankind. This duty is as pronounced
as though the community were attacked by bands of
ravenous wolves.”
Again:
“A leading editorial in an afternoon paper of the
city of Washington, of October 20, 1908, bears the
heading, ‘Typhoid a National Scourge,’ arguing that
it is to-day as great a scourge as tuberculosis. The
editorial writer might equally well have used the head-
ing ‘Typhoid a National Reproach,’ or perhaps even
‘Typhoid a National Crime,’ since it is an absolutely
preventable disease. And as for the typhoid fly, that a
creature born in indescribable filth and absolutely
swarming with disease germs should practically be in-
vited to multiply unchecked, even in great centers of
population, is surely nothing less than criminal.”
The whole bulletin (No. 78, Bureau of Entomol-
ogy) should be read and studied by all who are
interested in this subject.
House-Flies or Typhoid-Flies 75
OTHER FLIES
Occasionally other flies looking more or less like
the house-fly are seen in houses. Some of these
have the same type of sucking mouth-parts and
have habits very similar to the house-fly, but as
they are usually much less common and as nearly
all that has been said in regard to the house-fly
would apply equally well to them and as the same
measures should be adopted in fighting them they
need not be discussed further here.
I have already called attention to the fact that
a fly which looks very much like the house-fly is
sometimes found in the house and will often bite
severely. It has quite a different style of beak, one
that is fitted for piercing so it may suck the blood
of its victim (Fig. 51). As these flies often seem
to be more persistent before a rain the weather
prophet will tell you that ‘“‘It is surely going to rain
for the house-flies are beginning to bite.”’
These stable-flies, as they are called, are great
pests of cattle and horses in some sections. It is
thought that they are important factors in the
spread of some of the diseases of domestic animals,
and their habit of sometimes attacking human be-
ings makes it possible for them to carry certain
disease germs from animals to man or from man
to man.
CHAPTER VI
MOSQUITOES
OSQUITOES are no more abundant now
than they have been in the past, but
when Linnezus in 1758 made his list of
all the animals known to exist at that
time he catalogued only six species of mosquitoes.
Only a few years ago, 1901, Dr. Theobald of the
British Museum published a book on the mosqui-
toes of the world in which he listed three hundred
and forty-three kinds. Soon other volumes ap-
peared, adding more species, and _ systematists
everywhere have been describing new ones until
now the total number of described species is prob-
ably over five hundred, more than sixty of which
occur in the United States.
This shows only one phase of the great interest
that has been taken in the mosquitoes since the
discovery of their importance as carriers of disease.
Not only have they been studied from a systematic
standpoint but an endless amount of work has been
done and is being done in studying their develop-
76
Fic. 50
FIG. 52
1c. 50—Pupa of house-fly with the end broken to allow
the fly to issue.
Fic. 51—Head of stable-fly showing sharp piercing beak.
Fic. 52—Mass of mosquito eggs (Theobaldia incidens).
Fic. 53—Mosquito eggs and larvee (Theobaldia incidens); two
larvee feeding on bottom, others at surface to breathe.
Fic. 54—Mosquito larve (T. incidens), dorsal view.
Mosquitoes a7
ment, habits, and structure until now, if one could
gather together all that has been written about
mosquitoes in the last ten or twelve years he would
have a considerable library.
Those who are particularly interested in. the
group will find some of these books and papers
easily accessible, so there may be given here only
a brief summary of the more important facts in
regard to the structure and habits of the mos-
quitoes in order that we may more readily under-
stand the part that they play in the transmission
of diseases and see the reasonableness of the
recommendations in regard to fighting them.
THE EGGS
_ Mosquito eggs are laid in water or in places
where water is apt to accumulate, otherwise they
will not hatch. Some species lay their eggs in lit-
tle masses (Fig. 52) that float on the surface of
the water, looking like small particles of soot.
Others lay their eggs singly, some floating about
on the surface, others sinking to the bottom
where they remain until the young issue. Some
of the eggs may remain over winter, but usually
those laid in the summer hatch in thirty-six to
forty-eight hours or longer according to the tem-
perature.
78 Insects and Disease
THE LARVA:
When the larve are ready to issue they burst
open the lower end of the eggs and the young wrig-
glers escape into the water. The larve are fitted
for aquatic life only, so mosquitoes cannot breed
in moist or damp places unless there is at least
a small amount of standing water there. A very
little will do, but there must be enough to cover —
the larve or they perish.
The head of the larvee of most species is wide
and flattened. The eyes are situated at the sides,
and just in front of them is a pair of short antenne
which vary with the different species.
The mouth-parts too vary greatly according to
the feeding habits. Some mosquito larve are
predaceous, feeding on the young of other species
or on other insects. These of course have their
mouth-parts fitted for seizing and holding their
prey. Most of the wrigglers, however, feed on
alge, diatoms, Protozoa and other minute plant
or animal forms which are swept into the mouth
by curious little brush-like organs whose move-
ments keep a stream of water flowing toward the
mouth.
Another group containing the Anopheles are
intermediate between these two and have mouth-
parts fitted for feeding on minute organisms as
Fic. ss—Eggs, larve and pupe of mosquitoes (T. incidens),
Fic. 56—Larva of mosquito (T. incidens).
Fis. 5§7—Mosquito larve and pupae (T. incidens) with their
breathing-tubes at the surface of the water.
Fic. 58—Anopheles larvee (A. maculipennis) resting at the surface of
the water.
Mosquitoes 79
well as for attacking and holding other larger
things. |
A few kinds feed habitually some distance be-
low the surface, others on the bottom, while still
others feed always at the surface. With one or two
exceptions, the larvee must all come to the surface to
breathe (Figs. 53-57). Most species have on the
eighth abdominal segment a rather long breathing-
tube the tip of which is thrust just above the surface
of the water when they come up for air. In this
tube are two large vessels or tracheze which open
just below the tip of the tube and extend forward
through the whole length of the body, giving off
branches here and there that divide into still smaller
branches until every part of the body is reached
by some of the small divisions of this tracheal sys-
tem that carries the oxygen to all the tissues. The
length of the breathing-tube is correlated with the
feeding-habits of the larve. Anopheles larve
which feed at the surface have very short tubes
(Fig. 58), others that feed just below the surface
have breathing-tubes as long or very much longer
than the ninth abdominal segment. The last seg-
ment has at its tip four thin flat plates, the tra-
cheal gills. These too are larger or smaller ac-
cording to the habits of the larva. Those species
that feed close to the surface and have the tip of
80 Insects and Disease
the breathing-tube above the surface most of the
time have very small tracheal gills, while those that
feed mostly on the bottom have them well de-
veloped. :
When first hatched the larve are of course very
small. If the weather is warm and the food is
abundant they grow very rapidly. In a few days
the outer skin becomes rather firm and inelastic so
it will not allow further growth. Then a new skin
forms underneath and the old skin is cast off. This
process of casting off the old skin is called molting,
and is repeated four times during the one, two,
three or more weeks of larval life.
PUPA
With the fourth molt the active feeding larva
changes to the still active but non-feeding pupa
(Fig. 59). The head and thorax are closely united
and a close inspection will reveal the head, antenne,
wings and legs of the adult mosquito folded away
beneath the pupal skin. Instead of the breathing-
tube on the eighth segment of the abdomen as in
the larva, the pupa has two trumpet-shaped tubes
on the back of the thorax through which it now gets
its air from above the surface. The pupal stage
lasts from two to five or six days or more. When
the adult is ready to issue the pupal skin splits
Fic. 597—Mosquito pup (7. incidens) resting at the surface of
the water.
Fic. 60—Mosquito pupa (7. incidens) with its breathing-tubes in
an air bubbie below the surface of the water.
Fic. 61—Mosquito larve and pup (1. incidens) resting at the
surface of the water.
{
/ \
Fic. 62—A female mosquito (7, incidens); note the thread-like
antenne.
Fic. 63—A male mosquito (T. incidens); note the feathery antenne,
Mosquitoes 81
along the back and the mosquito gradually and
slowly issues. It usually takes several minutes
for the adult to issue and for its wings to become
hard enough so it can fly. In the meantime, it is
resting on the old pupal skin or on the surface of
the water, where it is entirely at the mercy of any
of its enemies that might happen along and is in
constant danger of being tumbled over should the
water not be perfectly smooth.
THE ADULT
The adult mosquito is altogether too familiar an
object to need description, but it is necessary that
we keep in mind certain particular points in re-
gard to its structure, in order that we may better
understand how it is that it is ened of trans-
mitting disease.
If we examine closely the antennz of a number
of mosquitoes that are bothering us with their too
constant attentions we shall see that they all look
very much alike (Fig. 62), small cylindrical joints
bearing whorls of short fine hairs. But if we
examine a number of mosquitoes that have been
bred from a jar or aquarium we will find two
types of antenne, the one described above belong-
ing to the female. The antenne of the male
(Fig. 63) aré much more conspicuous on account
82 Insects and Disease
of the whorl of dense, fine, long hairs on each
segment. Another interesting difference in the
antenne is to be noted in the size of the first joint.
In both sexes it is short and cup-shaped, but in the
male it is somewhat larger. This basal segment
contains a highly complex auditory organ which
responds to the vibrations of the whorls of hairs
on the other segments. Interesting experiments
have shown that these hairs vibrate best to the
pitch corresponding to middle C on the piano, the
same pitch in which the female “sings.” Of
course mosquitoes and other insects have no voice
as we ordinarily understand the word, but produce
sound by the rapid vibration of the wings or by the
passage of air through the openings of the trachee.
The males and females are thus easily distin-
guished and, as we shall see later, this is of some
importance for only the females can bite. The
males and females differ in another way. Just be-
low the antennz and at the sides of the proboscis or
beak is a pair of three- to five-jointed appendages,
the maxillary palpi or mouth-feelers which in the
females of most species are very short (Fig. 64)
while in the males they are usually as long as
the proboscis (Fig. 65). The females of Anopheles
and related forms have palpi quite as long as the
males, but they are slender throughout while the ©
Fic. 64—Head and thorax of female mosquito (Ochlerotatus lati-
vittatus); the short maxillary palpi are just above the proboscis
and below the thread-like antenn.
Frc. 65—Head and thorax of male mosquito (O. lativittatus); the
maxillary palpi are as long as the proboscis.
Fic. 66—Head of female mosquito (Anopheles), with mouth-
parts separated to show the needle-like parts: a, a antenn®;
b, b, palpi; c, labrum; d, d, mandibles; e, hypopharynx;
J. f, maxille; g, labium; h, labella. (After Manson.)
Fic. 67—Cross-section of proboscis of female (a) and male (0)
mosquito. Jxe, labrum-epipharynx; mn, mandibles; mx, maxille;
hp, hypopharynx; sal, salivary duct; Jz, labium; ir, trachea; mus,
muscles. (After Nuttall and Shipley.)
Mosquitoes 83
male palpi are usually somewhat enlarged toward
the tip and bear more or less conspicuous patches
of rather long hairs or scales.
THE MOUTH-PARTS
The mouth-parts of the mosquito are of course
of particular interest to us. At first they appear to
consist of a long slender beak or proboscis, but by
dissecting and examining with a microscope we
find this beak to be made up of several parts
(Fig. 66). The labium, which is the largest and
most conspicuous, is apparently cylindrical but is
grooved above throughout its length. At the tip
of the labium are the labelle, two little lobes which
serve to guide the piercing organs. Lying in this
groove along the upper side of the labium are six
very fine, sharp-pointed needles. The uppermost
of these, the labrum-epipharynx, or labrum as we
will call it, is the largest and is really a hollow tube
very slightly open on its under side. Just below
this is the hypopharynx, the lateral margins of
which are very thin. Down through the median
line of the hypopharynx runs a minute duct
(Fig. 67, sal) which, though exceedingly small, is of
very great importance, for through it is poured the
saliva which may carry the malaria germs into the
wound made when the mosquito bites. The other
84 Insects and Disease
four needles consist of a pair of mandibles which
are lance-shaped at the tip and a heavier pair
of maxillz, the tips of which are serrate on one
edge.
HOW THE MOSQUITO BITES
When the female mosquito is feeding on man or
any other animal the tip of the labium is placed
against the surface and the six needles are thrust
into the skin, the labelle serving as guides. As
they are thrust deeper and deeper the labium is
bowed back to allow them to enter. As soon as the
wound is made the insect pours out through the
tube of the hypopharynx some of the secretion from
the salivary glands and then begins to suck up
the blood through the hollow labrum into the
pharynx and on into the stomach.
The mouth-parts of the male differ in some im-
portant respects from those of the female. The
hypopharynx is united to the labium, the mandi-
bles are wanting and the maxilla are very much
reduced so that the insect is unable to pierce the
tough skin of animals. The male feeds on the
juices of plants as do the females when they can-
not get blood. It is not at all necessary for mos-
quitoes to have the warm blood of man or other
animals. Comparatively few of them ever taste
Mosquitoes 85
blood. They have been seen feeding on blossoms,
ripe fruit, watermelons, plant juices, etc. They
are very fond of ripe bananas and are fed on them
in the laboratory when we wish to keep mosquitoes
for experimental purposes.
THE THORAX
The middle part of the body, called the thorax,
is really a strong box with heavy walls for the at-
tachment of the powerful wing and leg muscles.
The three pairs of legs are covered with hairs and
scales, and their tips are provided with a pair of
claws which vary somewhat in the different spe-
cies. ‘The wings (Fig. 68) are long and narrow
with a characteristic venation. Along the veins
and the margin of the wings are the scales which
readily enable one to distinguish mosquitoes from
other insects that may look much like them. In
some species these scales are long and narrow, al-
most hair-like, in others they are quite broad and
flat (Fig. 69). Just back of the wings is a pair
of balancers, short thread-like processes knobbed
at the end. ‘These probably represent the second
pair of wings with which most insects are pro-
vided, and seem to serve as balancers or orienting
organs when the insect is flying. On the sides of
the thorax are two small slit-like openings, the
86 Insects and Disease
breathing-pores. ‘These are the openings into the
tracheal or respiratory system.
THE ABDOMEN
The long cylindrical abdomen is composed of
eight segments. ‘These are rather strongly chiti-
nized above and below, but a narrow strip along
the side is unchitinized. In this strip are situated
the abdominal breathing-pores. The tip of the
abdomen is furnished with a pair of movable
organs, which in the male are variously modified
and serve as clasping organs at mating time.
THE DIGESTIVE SYSTEM
The mouth-parts of the mosquito have just been
described. It will be remembered that the labrum
is provided with a groove. Through this the blood
or other food is sucked up by means of a strong-
walled pumping organ, the pharynx, situated in
the head (Fig. 70). Just back of the pharynx is the
esophagus which leads to the beginning of the
stomach. Close to its posterior end the esophagus
gives off three food reservoirs, two above and a
single larger one below. In dissections these will
often be seen to be filled with minute bubbles. ‘The
Stomach reaches from the middle of the thorax to
beyond the middle of the abdomen. At its pos-
LLG AOL ANTE ARAP n0 IPOS RE ERED Ie pret
ee
Fic. 68—Wing of Mosquito (O. lativittatus),
Fic. 69—End of mosquito wing highly magnifiel to show the
scales on the veins.
Cors«| reservoir Body
Ocsephiagus .
“7harynx
4
Intestine
SRomech
we Sanaa ree
Pi-oboscis Salivary glands
Fic. 70—Diagram to show the alimentary canal and _ salivary
glands of a mosquito.
Fic. 71—Salivary glands of Culex at right. Anopheles at left.
(After Christophers.)
Mosquitoes 87
terior end are given off five long slender processes,
the Malpighian tubules which are organs of excre-
tion, acting like the kidneys of higher animals.
The hindgut is that portion of the intestine from |
the stomach to the end of the body.
THE SALIVARY GLANDS
Lying under the alimentary canal in the forward
part of the thorax are the salivary glands. There
are two sets of these, each having three lobes with
a common duct which joins the duct from the other
set a short distance before they enter the base of
the hypopharynx. Each of these lobes is made up
of a layer of secreting cells (Fig. 71) which pro-
duces the saliva that is poured into the wound as
soon as the insect pierces the skin of the victim,
and we shall see, too, that the malarial germs also
collect in these glands to be carried by the saliva
to the new host.
EFFECTS OF THE BITE
After a mosquito has bitten a person and with-
drawn the stylets, a small area about the puncture
whitens, then soon becomes pink and begins to
swell, then to itch and burn. Some people suffer
much more from the bites of mosquitoes than do
others. For some such bites mean little or no in-
88 Insects and Disease
convenience, indeed may pass wholly unnoticed,
to others a single bite may mean much annoyance,
and several bites may cause much suffering.
After an hour or so the itching usually ceases,
but in some cases it continues longer. In some in-
stances little or no irritation is felt until some hours,
sometimes as much as a day, after the bite. In
such cases the effect of the bite is apt to be severe
and to last for several days. Sometimes a more or
less serious sore will follow a bite, probably due to
infection of the wound by scratching. It is doubt-
less the saliva that is poured into the wound that
causes the irritation. It is frequently asserted that
if the mosquito is allowed to drink its fill and with-
draw its beak without being disturbed no evil
results will follow. ‘Those who hold this theory
say that the saliva that is poured into the wound is
all withdrawn again with the blood if the mosquito
is allowed to feed long enough. There may be
some truth in this, but for most of us a bite means
a hurt anyway and few will be content to sit per-
fectly still and watch the little pest gradually fill
up on blood.
It is not known just what the action of the saliva
is, its composition or reaction on the tissues. It is
generally supposed to prevent coagulation of the
blood that is to be drawn through the narrow tube
Mosquitoes 89
of the labrum. Others think that its presence
causes a greater flow of blood to the wound. But
the sad part of it is, for us at least, that it hurts
and may cause malaria and possibly other dis-
eases.
HOW MOSQUITOES BREATHE
Mosquitoes and other insects do not have any
nostrils nor do they breathe through any open-
ings on the head. Along the sides of the thorax
and abdomen is a series of very minute open-
ings known as the spiracles. ‘Through these the
air passes into a system of air-tubes, the trachee.
There are two main trunks or divisions of the
trachez just inside the body-wall and a number of
shorter connecting trunks. From these larger
vessels arise a great number of smaller ones which
branch and subdivide again and again until all
the tissues are supplied by these minute little air-
tubes that carry the oxygen to all parts of the body
and carry off the waste carbon dioxid. These air-
tubes are emptied and filled by the contractions
of the walls of the abdomen. When the body-wall
contracts the air is forced out of the thin-walled
trachea through the spiracles; when the pressure
is removed they are refilled by the fresh air rushing
in.
go Insects and Disease
THE BLOOD
After a mosquito has been feeding on a man or
some other animal it is often so distended that the
blood shows rich and red through the thin sides of
the walls of the abdomen. This, however, is the
blood of the victim and not of the mosquito. The
blood of insects is not red but pale yellowish or
greenish. It is not confined in definite vessels, but
fills all the space inside the body cavity that is
not occupied by some of the tissues or organs.
It bathes the walls of the alimentary canal and
gathers there the nourishment which it carries to
all parts of the body. It does not carry oxygen or
collect the carbon dioxid as does the blood of
higher animals. ‘That work, as we have just seen,
is done by the air-tubes. Above the alimentary
canal, extending almost the whole length of the ab-
domen and thorax, is a thin-walled pulsating ves-
sel, the heart. This consists of a series of chambers
each communicating with the one in front of it by
an opening which is guarded by a valve. When
one of these chambers contracts it forces the blood
that is in it forward into the next chamber which, in
its turn, sends it on. As the walls relax the valves
at the sides are opened and the blood that is in the
body-cavity rushes in to fill the empty chamber.
Sateen ee
EG. 7/2 PiGs 73
Fic. 72—Heads of Culicine mosquitoes; a, male; b, female. (After Manson.)
Fic. 73—Heads of Anophelinz mosquitoes; c, male; d, female. (After
. Manson.)
Fic. 74—Wing of Anopheles maculipennis.
Fic. 75—Wing of Theobaldia incidens.
Pie. 79
Fic. 76—A non-malarial mosquito (T. incidens), female, standing on
1G:
IDE,
Fic.
Fic. 78
the wall.
77— Wale on Same:
78—A malarial mosqui
the wall.
79—Female of same.
to (A. maculipennis), male, standing on
Mosquitoes gI
As these regular rythmical pulsations recur the
blood is forced forward through the heart into the
head where it bathes the organs there. We shall
see in another chapter that the malarial parasite
escapes from the walls of the stomach of the mos-
quito into the blood in the body-cavity and finally
reaches the salivary glands. As the heart is con-
stantly driving blood to this part of the body the
parasites readily reach the glands from which they
finally escape into the new host.
CLASSIFICATION
For our purpose it will not be necessary to try to
give a system of classification of all the mosquitoes.
Those interested in this phase of the subject will
find several books and papers devoted wholly to it.
It is quite important, however, that we know
something about a few of the more familiar groups
and kinds, especially those concerned in the trans-
mission of diseases.
THE ANOPHELES
In pointing out the differences between male and
female mosquitoes we noted that in one group, the
genus Anopheles, both sexes have long maxillary
palpi (Figs. 72, 73). This is the most important
character separating this genus from the other
92 Insects and Disease
common forms and as the Anopheles are the ma-
laria carriers it is important that this difference be
remembered. Most of the members of this group
have spotted wings (Fig. 74), but as some other
common kinds also have spotted wings (Fig. 75)
this character will not always be reliable. When
an Anopheles mosquito is at rest the head and pro-
boscis are held in one line with the body and the
body rests at a considerable angle to the surface
on which it is standing. Other kinds rest with the
body almost or quite parallel to the surface on
which they are standing. So if you find a female
mosquito with long mouth-palpi and_ spotted
wings resting at an angle to the surface on which
- it stands you may be reasonably sure that it is an
Anopheles and therefore may be a (Figs.
70, 77; 78, 79):
In the United States there are three species of
Anopheles—maculipennis, punctipennis and cru-
cians—which are common in various localities,
and one or two other species that so far as known
are local or rare.
The Anopheles eggs are not laid in masses as are
the eggs of many other mosquitoes, but are de-
posited singly on the surface of the water where
they may be found often floating close together.
The eggs (Figs. 80, 81) are elliptical in outline
Fic. 80
IXgg of Anopheles, side view. (After
Nuttall and Shipley.)
Fic. 81—Egg of Anopheles, dorsal view. (After
Nuttall and Shipley.)
Fic. 82—Anopheles larve, the one to the right feeding.
Fic. 83—Anopheles larve, the one to the right feeding, the
other just coming to the surface
Fic. 84—Anopheles larva, dorsal view.
Fic. 85—Anopheles pupz resting at surface of water.
——_—.— ——-
Mosquitoes 93
and are provided with a characteristic membranous
expansion near the middle.
The larve may be found at the proper season
and in the localities where they are abundant in
almost any kind of standing water, in clear little
pools beside running streams, in the overflow from
springs, In swamps and marshy lands, in rain-
barrels or any other places or vessels where the
water is quiet. ‘They do not breed in brackish
water. As they feed largely on the alge or green
scum on the surface of the water they are espe-
cially apt to be found where this is present. We
have already noted that their positions in the water
differ from that assumed by other species (Fig. 82).
As the breathing-tube is very short the larve
must come close to the surface to breathe, and
when they are feeding we find them lying just un-
der and parallel to the surface of the water with
their curious round heads turned entirely upside
down as they feed on the particles that are float-
ing on the surface (Figs. 83, 84).
The pup do not differ very much from the
pupz of other species although the breathing-tubes
on the thorax are usually shorter and the creature
usually rests with its abdomen closer to the sur-
face, that is, it does not hang down from the surface
quite as straight as do other forms (Fig. 85).
94 Insects and Disease
The adults may be found out of doors or in
houses, barns or other outbuildings. They do not
seem to like a draft and consequently will be more
apt to frequent rooms or places where there is little
circulation of air. Although they are usually sup-
posed to fly and bite only in the evening or at night,
they may occasionally bite in the daytime. One
hungry female took two short meals from my arm
while we were trying to get her to pose for a photo-
graph one warm afternoon.
The female passes the winter in the adult con-
dition, hibernating in any convenient place about
old trees or logs, in cracks or crevices in doors or
out of doors. In the house they hide in the closets,
behind the bureau, behind the head of the bed, or
underneath it, or in any place where they are not
apt to be disturbed. During a warm spell in the
winter or if the room is kept warm they may come
out for a meal almost any time.
THE YELLOW FEVER MOSQUITO
Ranking next in importance to Anopheles as a
disseminator of disease and in fact solely responsi-
ble for a more dreaded scourge, is the species of
mosquito now known as Stegomyia calopus. While
this species is usually restricted to tropical or semi-
tropical regions it sometimes makes its appearance
Mosquitoes 95
in places farther north, especially in summer time,
where it may thrive for a time. The adult mos-
quito (Fig. 104) is black, conspicuously marked
with white. The legs and abdomen are banded
with white and on the thorax is a series of white
lines which in well-preserved specimens distinctly
resembles a lyre. ‘These mosquitoes are essentially
domestic insects, for they are very rarely found ex-
cept in houses or in their immediate vicinity. Once
they enter a room they will scarcely leave it except
to lay their eggs in a near-by cistern, water-pot, or
some other convenient place.
Their habit of biting in the daytime has gained
for them the name of “‘day mosquitoes” to distin-
guish them from the night feeders. But they will
bite at night as well as by day and many other
species are not at all adverse to a daylight meal, if
the opportunity offers, so this habit is not distinc-
tive. The recognition of these facts has a distinct
bearing in the methods adopted to prevent the
spread of yellow fever. There are no striking char-
acters or habits in the larval or pupal stages that
would enable us to distinguish without careful ex-
amination this species from other similar forms
with which it might be associated. For some time
it was claimed that this species would breed only in
clean water, but it has been found that it is not
96 Insects and Disease
nearly so particular, some even claiming that it
prefers foul water. I have seen them breeding in
countless thousands in company with Stegomyia
scutellaris and Culex fatigans in the sewer drains in
Tahiti in the streets of Papeete. As the larve feed
largely on bacteria one would expect to find them
in exactly such places where the bacteria are of
course abundant.
The fact that they are able to live in any kind of
water and in a very small amount of it well adapts
them to their habits of living about dwellings.
So far as known the members of these two
genera are the only two that are concerned in the
transmission of disease in the United States. In
other countries other species are suspected or
proven disseminators of certain diseases, but these
will be discussed in connection with the particular
diseases in later chapters.
OTHER SPECIES
The many other species of mosquitoes that we
have may be conveniently divided as to their
breeding-habits into the fresh-water and the
brackish-water forms. Among the fresh-water
kinds some are found principally associated with
man and his dwelling places, others live in the
woods or other places and so are far less trouble-
Mosquitoes 97
some. Most of these do not fly far. Several of the
species that breed in brackish water are great
travelers and may fly inland for several miles.
Thus the towns situated from one to three or four
miles inland from the lower reaches of San Fran-
cisco Bay are often annoyed more by the mos-
quitoes that breed only in the brackish water on
the salt marshes than they are by any of the
fresh-water forms (Figs. 86, 87). The worst mos-
quito pest along the coast of the eastern United
States and for some distance inland is a species
that breeds in the salt marshes.
NATURAL ENEMIES OF MOSQUITOES
In combating noxious insects we learned long
ago that often the most efficient, the easiest and
cheapest way is to depend on their natural ene-
mies to hold them in check. Under normal or
rather natural conditions we find that they are
usually kept within reasonable bounds by their
natural enemies, but under the artificial conditions
brought about by the settling and developing of any
district great changes come about. It very often
happens that these changes are favorable to the
development of the noxious insects and unfavorable
to the development of their enemies.
A striking example and one to the point is af-
98 Insects and Disease
forded in the introduction of mosquitoes into
Hawaii. Up to 1826 there were no mosquitoes on
these islands. It is supposed that they were intro-
duced about that time by some ships that were
trading at the islands. Indeed it is claimed that
the very ship is known that brought them over
from Mexico.
Once introduced they found conditions there
very favorable to their development, plenty of
standing water and few natural enemies to prey on
them, so they increased very rapidly and gradually
spread over all the islands of the group. This was
the so-called night mosquito, Culex pipiens. Much
later another species, Stegomyia calopus, just as
annoying and much more dangerous was intro-
duced and has also become very troublesome. We
have a few species of top-minnows (Fig. 88) occur-
ring in sluggish streams in the southern part of the
United States that are important enemies of the
mosquitoes of that region. A few years ago some
of these were taken over to Hawaii and liberated
in suitable places to see if they would not help solve
the mosquito problem there. The fishes seem to be
doing well. Already they are destroying many
mosquito larve, and there are indications that they
are going to do an important work, but of course
can be depended on only as an aid.
Fic. 86—Salt-marsh mosquito (Ocalerotatus lativittatus);
male.
Fic, 87—Salt-marsh mosquito (O, lativittatus); female.
Fic. 88—Top-minnow (Mollienisia latipinna). (From
Bull., 47 U.S. Fish Com.)
‘
\
|
AF
ay
Fic. 89—Dragon-flies. (From Kellogg’s Amer. Insects.)
Mosquitoes 99
On account of the various habits of both the
larvee and adults it will never be possible for any
natural enemy or group of natural enemies effect-
ively to control the mosquitoes of any region, but
as certain of them are important as helpers they
deserve to be mentioned. |
ENEMIES OF THE ADULTS
Birds devour a few mosquitoes, the night-flying
forms being particularly serviceable, but the num-
ber thus destroyed is probably so small as to be of
little practical importance.
The dragon-flies (Figs. 89, 90, 91) or mosquito
hawks have long been known as great enemies
of mosquitoes, and they certainly do destroy many
of them as they are hawking about places where
mosquitoes abound. Dr. J. B. Smith of New Jer-
sey very much doubts their efficiency, but obser-
vations made by other scientific men would seem
to indicate that they often devour large numbers
of mosquitoes during the course of the day and
evening.
Spiders and toads destroy a few mosquitoes each
night. Certain external and internal parasites de-
stroy a few more, but the sum total of all of these
agencies is probably not very considerable, for
_ while the adults may have several natural enemies
100 Insects and Disease
they are not of sufficient importance to have any
appreciable effect on the number of mosquitoes in
a badly infested region.
ENEMIES OF THE LARVZ AND PUP
The larve and pupz on the other hand have
many important enemies. Indeed under favorable
conditions these may keep small ponds or lakes
quite free from the pests. The predaceous aquatic
larvee of many insects feed freely on wrigglers.
The larve of the diving beetles which are known
as water-tigers are particularly ferocious and will
soon destroy all the wrigglers in ponds where they
are present (Fig. 92). Dragon-fly larvee also feed
freely on mosquito larve. Whirligig beetles are
said to be particularly destructive to Anopheles
larve and many other insects such as water-
boatmen, back-swimmers, etc., feed on the larve
of various species. A few of these introduced into
a breeding-jar with Anopheles larve will soon de-
stroy all of them, even the very young bugs attack-
ing larve much larger than themselves.
It is interesting to note that the larve of some
mosquitoes are themselves predaceous and feed
freely on the other wrigglers that may chance to -
in the same locality.
Various species of fish are, however, the most im-
sS Uh
J *
ow
" ul
Fic. go—The young (nymph) of
a dragon-fly. (From Keliogg’s
Amer. Insects.)
Fic. gt—The cast skin (exuviec) of a dragon-fly nymph.
Fic. 92—Diving-beetles and back-swimmers. (From Kellogg’s Amer.
Insects.)
Mosquitoes 101
portant enemies of the mosquitoes. Great schools
of tide-water minnows (Fig. 93) are often carried
over the low salt-marshes by the extreme high-
tides and left in the hundreds of tide pools as the
tide recedes. No mosquitoes can breed in a pool
thus stocked with these fish. In the fresh-water
streams and lakes there are several species of the
top-minnows, sticklebacks (Fig. 94), etc., that feed
voraciously on mosquito larvee and unless the grass
or reeds prevent the fish from getting to all parts of
the ponds or lakes very few mosquitoes can breed
in places where they are present.
Minute red mites such as attack the house-flies
and other insects sometimes attack adult mosqui-
toes, but they are rarely very abundant. Parasitic
roundworms attack certain species. Others suffer
more or less from the attacks of various Sporozoan
parasites.
FIGHTING MOSQUITOES
When mosquitoes are bothering us we usually
begin by trying to kill the individual pests that are
nearest to us. We try to crush them if they bite us;
we screen the doors and windows to keep them
from the house. In warmer countries the people
are a little more hospitable and do not screen the
mosquitoes out of the house entirely, but screen the
beds for protection at night, and if the mosquitoes
102 Insects and Disease
get too insistent during the day the bed makes a
safe and comfortable retreat. All the mosquitoes in
a room may be killed by fumigating with sulphur at
the rate of two pounds to the thousand cubic feet of
air-space. Pyrethrum is also used largely, but it
only stupefies the mosquitoes temporarily instead of
killing them. While in that condition they may be
swept up and destroyed.
Various substances are sometimes used as re-
pellants by those who must be in regions where the
mosquitoes are abundant. With many of these,
however, ‘‘the cure is worse than the disease.”
Smudges are often built to the windward of a house
or barn-yard and the smoke from a good smoldering
fire will keep a considerable area quite free from
mosquitoes. ‘The man who can keep himself en-
veloped in a cloud of tobacco smoke will not be
bothered by mosquitoes. Oil of pennyroyal, oil of
tar or a mixture of these with olive oil, and various
other concoctions are sometimes smeared over the
face and hands. ‘These will furnish protection as
long as they last. Dr. Smith says that he has
found oil of citronella quite effective and of course
less objectionable than the other things usually
used. Care should be taken not to get it in the
eyes. An ointment made of cedar oil, one ounce;
oil of citronella, two ounces; spirits of camphor,
Tic. 93—Killifish (Fundulus heteroliatus). (From Bull. 47, U.S. Fish Com.)
Fic. 94—Stickleback (A peltes quadracus). (From Bull. 47, Ues: Fish Com:)
4 yf
“a ee
Fic. g5—An old watering trough, an excellent breeding-place for mosquitoes.
Mosquitoes 103
two ounces, is said to make a good repellant and is
effective for a long time.
FIGHTING THE LARVA:
All of the efforts directed against the adult mos-
quitoes are usually of little avail in decreasing the
number in any region. It is comparatively easy,
however, to fight them successfully in the larval
stage. We have seen that standing water is abso-
lutely necessary for mosquitoes to breedin. ‘This
makes the problem much simpler than if they
could breed in any moist places such as well-
sprinkled lawns, a shady part of the garden, etc.
The whole problem of successful campaigns
against the mosquitoes resolves itself into the prob-
lem of finding and destroying or properly treat-
ing their breeding-places. We have seen how cer-
tain kinds, such as the yellow fever mosquito, are
“domestic”? species.. They never go far from
their breeding-places. Ifa house is infected by one
of these species the immediate premises should be
searched for the source. Cisterns, rain-barrels,
sewer-traps, cesspools, tubs or buckets of water or
old tin cans in out-of-the-way corners, are all suit-
able places for them to breed in. Cisterns and rain-
barrels should be thoroughly screened so that no
mosquitoes can get in or out, or the surface should
104 Insects and Disease _
be covered with a film of kerosene which will kill all
the larvee in the water when they come to the sur-
face to breathe, and will also kill the females when
they come to deposit their eggs. ‘The vent to open
cesspools should be thoroughly screened or the
surface of the water kept well covered with oil.
Water standing in any vessels in the yards should
be emptied every week or ten days and the old tin
cans destroyed or hauled away. In fighting these
domestic species you need be concerned only with
your own yard and that of your near-by neighbors.
Other species, while also rather local in their dis-
tribution, fly much farther than the really domestic
ones. In fighting these the region for a consid-
erable distance around must be taken into consid-
eration. Watering-troughs (Fig. 95) that are left
filled from week to week, the overflow from such
places, and the tracks made in the mud round
about them (Fig. 96), small sluggish streams, irri-
gating ditches, and small ponds or lakes not sup-
plied with fish are excellent breeding-places for sev-
eral species of mosquitoes including Anopheles and
others. The remedy at once suggests itself. The
watering-trough can be emptied and renewed every
week during the summer time, the overflow can be
taken care of in a ditch that will lead it away from
the trough to where it will sink into the ground, the
Mosquitoes 105
banks of the streams or ponds or lakes can be
cleared in such a way that fish can get to all parts of
the water; most of the small ponds can be drained or
their surface may be covered over with a thin film of
kerosene. This is best applied as a spray; one
ounce to fifteen square feet will suffice. If the oil is
simply poured over the surface more will be required.
The fighting of the species that breed on the ex-
tensive salt-marshes in many regions is a larger
and more difficult problem, but as it is a matter
that usually concerns large communities, sometimes
whole states, it can be dealt with on a larger scale.
The very excellent results that have been accom-
plished in New Jersey and on the San Francisco
peninsula, and in a smaller way in other places,
show what may be done if the community goes
about the fight in an intelligent manner. In the
fight in New Jersey hundreds of acres of tide-lands
have been drained so that they no longer have tide
pools standing where the mosquitoes may breed.
When it is impracticable to drain them the pools
may be sprayed occasionally with kerosene.
The value of the land that is reclaimed by a good
system of draining is often enough to pay many
times over the cost of draining, thus the mosquitoes
are gotten rid of and the land enhanced in value by
a single operation.
CHAPTER VII
MOSQUITOES AND MALARIA
ma VER since the beginning of history we
have records of certain fevers that have
been called by different names accord-
ing to the people that were affected.
As we study these names and the various writings
concerning the fevers we find that a great group
of the most important of them are what we to-day
know as malarial fevers. Not only are these ills
as old as history but they have been observed over
almost the entire inhabited earth. ‘There are cer-
tain regions in all countries where malaria does
not occur, but almost always it will be found that
other regions near by are infected and it very often
happens that these infected regions are the most
profitable parts of the land, the places where water
is plentiful and vegetation is luxuriant. Indeed
the coincidence of these two things, low-lying lands
with an abundance of water, particularly stand-
ing water,and malaria has always been noted and
gave rise to the earliest theories in regard to the
cause of the disease.
106
Mosquitoes and Malaria 107
For instance, we find some of the very early
writers emphasizing the point that swampy locali-
ties should be avoided for they produce animals
that give rise to disease, or that the air is poisoned
by the breath of the swamp-inhabiting animals.
These views of the origin of the fever prevailed
until about the beginning of the eighteenth century
when the recently discovered microscope began to
reveal the various kinds of animalcule to be found
in decaying material.
In 1718 Lancisi held that the myriads of insects,
particularly gnats or mosquitoes, that arose from
such swampy regions might carry some of these
poisonous substances and by means of their pro-
boscis introduce them into the bodies of the people,
and although he had made no experiments to test
the assumption he did not consider it impossible
that such insects might also introduce the smallest
animalcule into the blood. It took almost two
centuries of study and investigation before this
guess was proved to be right.
One reason why the mosquitoes were not earlier
associated with these diseases was that all who in-
vestigated the matter at all turned their attention
to the bad condition of the air in these swampy
regions. Malaria means bad air. We all know
that we can see the mists arising from such regions,
108 Insects and Disease
particularly in the evening or at night, and as ex-
posure to these mists very often meant an attack —
of malaria they were naturally supposed to be the
cause of the disease. So for a long time the whole
attention of investigators was turned toward study-
ing and analyzing these vapors, and various experi-
ments were made which seemed to show conclu-
sively that the malaria was caused only by these
emanations. The investigations even went so far
that the exact germs that were supposed to cause
the fever were separated and experimented with.
THE PARASITE THAT CAUSES MALARIA
The blood had been studied time and again and
the characteristic appearance of the blood of a
malarial patient was well known. In 1880 Lave-
ran, a French army surgeon in Algiers, began to
study the blood of such patients microscopically -
and soon was able to demonstrate the parasite
that caused the disease. His discoveries were not
readily accepted, but other investigations soon con-
firmed his observations and the fact was gradually
firmly established. Not until recently, however,
did this distinguished physician receive a full rec-
ognition of his work. A few years ago he was
awarded the Nobel prize for medicine, perhaps the
highest honor that can be bestowed on any physician.
F'1c. 96—Horse and cattle tracks in mud filled with water; good
breeding-places for Anopheles.
Fic. 97—-A malarial mosquito (Anopheles maculipennis); male.
Fic. g8—A malarial mosquito (A. maculipennis); female.
Mosquitoes and Malaria 109
It is interesting, too, to note in this connection that it
was another French surgeon who in 1840 discovered
that sulphate of quinine is a specific for malaria.
The next important step was made in 1885 by
Golgi, an Italian, who studied the life-history of the
parasite in the blood and distinguished the three
forms which cause the three most familiar kinds
of malarial fevers, the tertian, the quartan and the
remittent types. From this time on this parasite
has been studied by physicians of many nationali-
ties and the whole course of its life-history worked
out. In order that we may understand how it was
that mosquitoes were determined to be the means
of disseminating this parasite we will discuss first
its life-history in the human blood.
The parasites that cause the malarial fevers are
Sporozoans and belong to the genus Plasmodium.
Other names such as Hemameba and Laverania
have been used for them, but the term Plasmodium
is the one now most commonly employed. The
three most common species are vivax, malarie
and falciparum, causing respectively the tertian,
quartan and remittent fevers.
LIFE-HISTORY OF PARASITE
The life-history of all of these is very similar, the
principal difference being in the length of time it
110 Insects.and Disease
takes them to sporulate. Let us begin with the
parasite after it has been introduced into the blood
and trace its development there. At first it is slen-
der and rod-like in shape. It has some power of
movement in the blood-plasm. Very soon it at-
tacks one of the red blood-corpuscles and gradually
pierces its way through the wall and into the cor-
puscle substance (Fig. 99); here it becomes more
amcoeboid and continues to move about, feeding all
the time on the corpuscle substance, gradually de-
stroying the whole cell. As the parasite feeds and
grows there is deposited within its body a blackish
or brownish pigment known as melanin.
During the time that the parasite is feeding and
growing it is also giving off waste products, as all
living forms do in the process of metabolism, but as
the parasite is completely inclosed in the corpuscle
wall these waste products cannot escape until the
wall bursts open. After about forty hours if the
parasite is vivax or about sixty-five hours if it is
malarie it becomes immobile, the nucleus divides
again and again and the protoplasm collects around
these nuclei, forming a number of small cells or
spores, as they are called. In about forty-eight or
seventy-two hours, depending on whether the para-
site is vivax or malarié the wall of the corpuscle
bursts and all these spores with the black pigment
Some may be taken
into the stomach
\ 4 of the Mosquito when
Develooment. of it bites
ar ©} p . .
arasite |
8 0 9 ein ~~
val \ © 06% __ Human Blood \
(3 fo) UN } v
G45 re :
ES | on
E Bo 5. Jo
SEs ; 5 a’
Oo c2 oO :
ee
ao InSal Devel t
7) nOalivar eveiopmen
Gland. P
rs of Mosq.
in the
Mosquito
Jo yoeWOIS U! JUaWdy
feat
sow
(@)
i)
e.
Fic. 99—Diagram to illustrate the life-history of the malarial para-
site. 1 is a red blood-corpuscle, 2 to 7 shows the development of the
parasite in the corpuscle, a b c d and a’ 0’ c’ and e the development of
the parasite in the stomach of the mosquito, f g h 7 the development
in the capsule on the outer wall of the stomach of the mosquito, # in
the salivary gland.
Soe = mo
Fic. 10o0o—Malarial mosquito (A. maculipennis) on the
wall.
Fic. to1—Malarial mosquito (A. maculipennis) standing on a table.
Mosquitoes and Malaria III
and the waste products that have been stored away
within the cell are liberated into the blood-plasm.
These spores are round or somewhat amceboid
and are carried in the blood for a short time. Very
soon, however, each one attacks a new red cor-
puscle and the process of feeding, growth and
spore-formation continues, taking exactly the same
time for development as in the first generation, so
every forty-eight hours in the case of the vivax, and
every seventy-two hours in the case of the malariae
a new lot of these spores and the accompanying
waste products are thrown out into the blood.
Thus in a very short time many generations of
this parasite occur and thousands or hundreds of
thousands of the red-blood corpuscles are destroyed,
leaving the patient weak and anemic. It will be
seen, too, that the recurrence of the chills and fevers
is simultaneous with the escaping of the parasites
from the blood-corpuscles, together with the waste
products of their metabolism.
These waste products are poisonous, and it is be-
lieved that this great amount of poison poured into
the blood at one time causes the regular recurring
crisis. Zodlogists well know that this process of
asexual reproduction, 2. e., reproduction without
any conjugation of two different cells, cannot go on
indefinitely, and those who were studying the life-
112 Insects and Disease
cycle of these parasites were at a loss to know
where the sexual stage took place. In the mean-
time studies of other parasites more or less closely
related to Plasmodium showed that the sexual stage
occurred outside the vertebrate host. The remark-
able work of Dr. Smith on the life-history of the
germ that causes the Texas fever of cattle had
a strong influence in directing the search for this
other stage of the malarial parasite. Another thing
that indicated that this sexual generation must —
take place outside the body of the vertebrate host
was the fact that the investigators found that the
parasites in certain of the cells did not sporulate
as did the others. When these individuals were
drawn from the circulation and placed on a slide
for study it was found that they would swell up and -
free themselves from the inclosing corpuscle and
some of them would emit long filaments which
would dart away among the corpuscles.
Many men have worked on this problem, but
perhaps the most credit for its solution will always
be given to Sir Patrick Manson, the foremost au-
thority on tropical diseases, and to Ronald Ross, a
surgeon in the English army. There is no more
interesting and inspiring reading than that which
deals with the development of the hypothesis by
Manson and the persistent faith of Ross in the
Mosquitoes and Malaria 113
correctness of this theory, and his continuous in-
defatigable labors in trying to demonstrate it. It
was an important piece of scientific work, and
_shows what a man can do even when the obstacles
seem insurmountable.
THE PARASITE IN THE MOSQUITO
Briefly stated again, the problem was this: We
have here a parasite in the blood which behaves as
do many other forms of life. Some of these para-
sites do not go on with their development until
they are removed from the circulation. Now, how
are they thus removed from the circulation under
normal conditions? ‘This must first be solved be-
fore the still greater and more important problem
of how the parasite gets from one human host to
another can be taken up. In studying this over
Manson reasoned that certain suctorial insects were
the agencies through which blood was most com-
monly removed from the circulation and he ven-
tured the guess that this change in the parasite
that may be seen taking place on the slide under
the microscope, normally takes place in the stom-
ach of some insect that sucks man’s blood. Ross
was greatly impressed with the theory and began
his long and apparently hopeless task of finding
these parasites in the stomach of some insect.
114 Insects and Disease
When we remember that they are so minute that
they can only be seen by the use of the highest
power of the microscope we can realize something
of the magnitude of the task. Ross, who was at
that time stationed in India, selected the mosquito
as the most likely of the insects to be the host that
he was looking for. For over two and one-half
years he worked with entirely negative results, for
after examining thoroughly many thousands of
mosquitoes he found no trace of the parasite.
Practically all his work was done on the most
common mosquito of the region, a species of Culex.
But one day a friend sent him a different mosquito,
one with spotted wings, and in examining it he
was interested to note certain oval or round nodules
on the outer walls of the stomach. On closer ex-
aminations he found that each of these nodules con-
tained a few granules of the coal-black melanin of
malarial fever. Further studies and experiments
showed that these particular cells could always be
found in the walls of the stomach of this particular
species of mosquito a few days after it had bitten
a malarial patient. This epoch-making discovery
was made in 1898. Ross was detailed by the Eng-
lish government to devote his whole time to the
further solution of the problem, and after two
years more of careful experimentation and study
Mosquitoes and Malaria 115
was able to give a complete life-history of this
parasite. His experiments have been repeated
many times, and the conclusions he arrived at are
as undeniable as any of the known facts of science.
The whole life-history as we now know it can
be summed up as follows: The parasites develop
within the circulation but certain of them seem to
wander about and do not go on with their devel-
opment there. When these particular parasites are
taken into the stomach of most mosquitoes they
are digested with the rest of the blood. But when
they are taken into the stomach of a mosquito
belonging to the genus Anopheles or other closely
related genera they are not digested but go on with
their development, conjugation and fertilization
taking place, resulting in a more elongated form
which makes its way through the walls of the stom-
ach on the outside of which are formed the little
nodules discovered by Ross on his mosquitoes.
Within these nodules further division and develop-
ment takes place until finally the nodule is burst
open and many thousand minute rod-like organ-
isms, sporozoites, are turned loose into the body-
cavity of the mosquito. Owing to some unknown
cause these little organisms are gathered together
in the large vacuolated cells of the salivary glands
of the mosquito, and when the mosquito bites a
116 Insects and Disease
man or any other animal they pour down through
the ducts with the secretion and are thus again in-
troduced in the circulation.
The nodules or cysts on the walls of the stom-
ach of the mosquito may contain as many as ten
thousand sporozoites, and as many as five hundred
cysts may occur on a single stomach.
It takes ten, twelve or more days from the time
the parasites are taken into the stomach of the
mosquito before they can go through their trans-
formations and reach the salivary gland, the time
depending on the temperature. So it is ten or
twelve days or sometimes as much as eighteen or
twenty days from the time an Anopheles bites a ma-
larial patient before it is dangerous or can spread
the disease. On the other hand, the sporozoites
may lie in the salivary gland alive and virulent for
several weeks. It does not give up all the para-
sites at one time, so that three or four or more
people may be affected by a single mosquito.
It is well known that two parasites may often
be seen in the same corpuscle. This is often simply
a case of multiple infection, but Dr. Craig has very
recently shown that under certain conditions two
individuals may enter the same corpuscle and con-
jugate and the resulting individual will be resistant
to quinine and may remain latent in the spleen or
Mosquitoes and Malaria 117
bone marrow for a long time. Under favorable
conditions it may again begin the process of mul-
tiplication and the patient will suffer a relapse.
SUMMARY
Now let us sum up some of the reasons why we
believe that the malaria fever can be transmitted
only through the agency of mosquitoes. First,
we know the life-history of the parasite, it has
been studied in both of its hosts. Attempts have
been made to rear it in other hosts but without
avail, and we know from the general relations of
the parasite that it must have this sexual as well
as the asexual generations. Second, in some re-
gions which would seem to be malarial, that is,
where the miasmatic mists arise, no malaria occurs.
Why? Usually it can be definitely shown that no
Anopheles occur there. Other mosquitoes may be
there in abundance, but if no Anopheles, there is
no malaria. In certain regions this is well demon-
strated. ‘The west coast of Africa is one of the
worst pest-holes of malaria and Anopheles. ‘The
east coast has no malaria and no Anopheles. In
many islands the same condition exists. On the
other hand, the Fiji Islands have Anopheles but
no malaria. No malaria has ever been introduced
there to infect the mosquitoes. In the same way
118 Insects and Disease
Stegomyia occurs in some of the South Sea islands
and yet there is no yellow fever there.
EXPERIMENTS
We may review, too, a few of the classic experi-
ments that have served to show that malaria can be
contracted in no other way than through the bite
of the mosquito.
For many years Grassi, an Italian, devoted re
most his whole time to the study of malaria. In
1900 he received permission from the government
to experiment on the employees of a piece of rail-
road that was being built through a malarial
region. ‘This was divided for the purpose of the
experiment into three sections, a protected zone
in the middle and an unprotected zone at each end.
Those working in the protected zone had their
houses completely screened and no one was al-
lowed out of doors after sunset except they were
protected with veils and gloves. Early in the
season they were all given doses of quinine to pre-
vent auto-infection. In the unprotected zone no
screens were used and every one was allowed to
go without special protection. The result for the
summer was that there were no new cases of fever
in the protected zone. In the unprotected zones
practically all had the fever as usual.
Fic. 102—Salt-marsh mosquito (O. lafzvittatus) standing on a table
Fic. 103—Anopheles hanging from the ceiling.
Mosquitoes and Malaria 119
In the same year two English physicians, Sam-
bon and Low, went to Italy where they built a
cabin in one of the marshes noted as being a
malaria pest-hole. The house was thoroughly
screened so that no mosquitoes could enter, but the
windows were always open so as to admit the air
freely day and night. Here they lived for three
months, out of doors as much as they pleased dur-
ing the day but inside where they were protected
from the mosquitoes at night. No quinine was
used and no fever developed, although all about
them other people were having the fever as usual.
Another English physician who had not been
in malarial regions allowed himself to be bitten by
infected mosquitoes sent from a malarial locality.
In due time he developed the fever. Many other
experiments made in various places might be cited.
The results have all been practically the same. 'To-
day the soldiers of many civilized nations are re-
quired to protect themselves from mosquitoes be-
cause it has been found that it pays. Disease has
always been a worse terror than bullets in any war,
and we are fast learning that the great loss from
diseases heretofore considered unavoidable may be
very largely eliminated by proper sanitary arrange-
ments and protection from noxious insects.
CHAPTER VIII
MOSQUITOES AND YELLOW FEVER
g|ELLOW fever is a disease, principally
of seaport towns, from which the United
States has suffered more than any other
country. It is endemic only in tropical
regions but is often carried to subtropical, some-
times even to temperate zones where, if the proper
mosquitoes exist, it may rage until frost.
Vera Cruz, Havana, Rio de Janiero, and the
west coast of Africa were long regarded as per-
manent endemic foci, the disease appearing there
in epidemic form from time to time, often spread-
ing to other ports in more or less close communi-
cation with such places. In the United States the
Gulf states have been the greatest sufferers from
the disease, although it has spread as far as Balti-
more, Philadelphia and Washington, where at rare
intervals it was most serious, abating its ravages -
only when frost came.
The last severe outbreak occurred in New Or-
leans in 1905 when eight thousand cases and nine
120
Mosquitoes and Yellow Fever 121
hundred deaths occurred. At that time there was
waged one of the most remarkable warfares against
death in its most terrifying form that the world
has ever known. And, thanks to the achievements
of science, particularly to the investigations of
three men, one of whom gave his life to the cause,
the fight was successful and this dreadful outbreak
_ was checked just at the time when according to all
precedent it should have been at its height.
This result which at other times and under other
conditions would have been considered miraculous
was achieved not by the usual custom of isolation,
quarantine, etc., but by a direct, we may almost
say hand to hand, conflict with mosquitoes: the
mosquitoes belonging to a particular genus and
species, Stegomyza calopus (fasciatia).
Before taking up a discussion of this achieve-
ment in New Orleans let us consider first the work
of the men that made such results possible.
For many years the cause and methods of dis-
semination of this disease had been a puzzle to
physicians and scientists. Very early it was be-
lieved that it might be transmitted through the
air, and the fact that infection usually occurred in.
the vicinity of the water and in the tropics or in
midsummer led to the belief that the disease was
due to fermentation. ‘This theory received strong
122 Insects and Disease
' support in the fact that serious outbreaks of the
fever often followed the coming into port of vessels
from the tropics with the water in their holds in an
offensive condition. When it was discovered that
bacteria were the cause of fermentation and also of
many diseases this theory was considered abun-
dantly proven. From time to time, announcements
have been made that the particular species of bac-
teria that causes the disease has been isolated, but
there has always been something lacking in the
final proof.
Yellow fever has always been regarded as a very
highly contagious as well as infectious disease, and
the utmost precaution has been taken to isolate the
patients when possible and in recent years strict
quarantines have been established against infected
localities and no person or commerce or even the
mails were allowed to come from such places with-
out thorough fumigations. But all these things
proved unsatisfactory. ‘The disease could not or-
dinarily be checked by simply isolating the patients.
Many people became sick without ever having been
near a yellow fever patient, while others worked in
direct daily contact with the disease and did not
suffer from it. Those who had once had it and re-
covered became practically immune, rarely suffer-
ing from a second attack. Negroes may suffer
Fic. 104—Yellow-fever mosquito (Stegomyia calopus).
(R. Newstead, del.)
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i
ed
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are ges
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Mosquitoes and Yellow Fever 123
from the disease, but are usually regarded as prac-
tically immune.
It was early observed, too, that the danger zone
might be quite well defined and that outside this
zone one would be safe. More than a century
ago the British troops and other inhabitants of Ja-
maica found that by retreating to the mountains
during the warm weather the non-immunes could
escape the fever. It was also observed that those
who slept on the first floor were more apt to take
the disease than those on the second floor.
THE YELLOW FEVER COMMISSION
In 1900, during the American occupation of
Cuba, yellow fever became very prevalent there.
A board of medical officers was ordered to meet in
Havana for the purpose of studying the disease
under the favorable opportunities thus afforded.
This board, which came to be known as the Yellow
Fever Commission, was composed of Drs. Walter
Reed, James Carroll, Jessie W. Lazear and Aristi-
des Agramonte of the United States Army. Agra-
monte was a Cuban and an immune, the others
were non-immunes. Dr. Manson in his lectures on
Tropical Medicines says of them:
“TI cannot pass on, however, to what I have to say
in connection with this work without a word of admira-
124 Insects and Disease
tion for the insight, the energy, the skill, the courage,
and withal the modesty and simplicity of the leader
of that remarkable band of workers. If any man de-
served a monument to his memory, it was Reed. If
any band of men deserve recognition at the hands of
their countrymen, it is Reed’s colleagues.”
Their first work was to determine whether any
of the germs that had been claimed to be the
cause of yellow fever were really responsible for
the disease. Bacillus icteroides that for some time
and by some investigators had been named as the
offender was particularly investigated, but was
proved to be a secondary invader only.
Dr. Charles Finlay of Havana had been claiming
for some years that the yellow fever was trans-
mitted by means of the mosquito and possibly by
other insects also. He even claimed to have proved
this theory experimentally. We know now, how-
ever, that there must have been errors in his ex-
periments and that his patients became infected
from sources other than those he was dealing with.
The Yellow Fever Commission decided to put
this theory to the test and secured a number of
volunteers for the experiments. The first thing
was to let an infected mosquito bite some non-
immune person. How this was done and the re-
sults, may be told in Dr. Carroll’s own words.
Mosquitoes and Yellow Fever = 125
EXPERIMENTS
“Two separate lines of work now presented: one,
the study of the bacterial flora of the intestine and
anaérobic cultures from the blood and various organs;
the other, the theory of the transmission of the disease
by the mosquito, which had been advanced by Dr. Car-
los Finlay in 1881. After due consideration it was de-
cided to investigate the latter first. Then arose the
question of the tremendous responsibility involved in
the use of human beings for experimental purposes.
It was concluded that the results themselves, if positive,
would be sufficient justification of the undertaking. It
was suggested that we subject ourselves to the same
risk and this suggestion was accepted by Dr. Reed and
Dr. Lazear. It became necessary for Dr. Reed to re-
turn to the United States and the work was begun
by Dr. Lazear, who applied infected mosquitoes to a
number of persons, himself included, without result.
On the afternoon of July 27, 1900, I submitted myself
to the bite of an infected mosquito applied by Dr. La-
zear. ‘The insect had been reared and hatched in the
laboratory, had been caused to feed upon four cases
of yellow fever, two of them severe, and two mild. The
first patient, a severe case, was bitten twelve days be-
fore; the second, third and fourth patients had been
bitten six, four and two days previously, and were in
character mild, severe and mild respectively. In writ-
ing to Dr. Reed that night of the incident, I remarked
126 Insects and Disease
jokingly that if there was anything in the mosquito
theory, I should have a good dose. And so it happened.
After having slight premonitory symptoms for two
days, I was taken sick on August 31, and on Septem-
ber 1, I was carried to the yellow fever camp. My life
was in the balance for three days, and my chart shows
that on the fifth, sixth and seventh days my urine con-
tained eighth-tenths and nine-tenths of moist albumin.
On the day I was taken sick, August 31, 1900, Dr. La-
zear applied the same mosquito, with three others, to
another individual who suffered a comparatively mild
attack and was well before I had left my bed. It so
happened that I was the first person in whom the mos-
quito was proved to convey the disease.
“On the eighteenth of September, five days after I
was permitted to leave my bed, Dr. Lazear was stricken,
and died in convulsions just one week later, after sev-
eral days of delirium with black vomit. Such is yellow
fever.
‘He was bitten by a stray mosquito while applying
the other insects to a patient in one of the city hospitals.
He did not recognize it as a Stegomyia, and thought
it was a Culex. It was permitted to take its fill and he
attached no importance to the bite until after he was
taken sick, when he related the incident to me. I
shall never forget the expression of alarm in his eyes
when I last saw him alive in the third or fourth day
of his illness. The spasmodic contractions of his dia-
phragm indicated that black vomit was impending, and
Mosquitoes and Yellow Fever 127
he fully appreciated their significance. The dreaded
vomit soon appeared. I was too weak to see him again
in that condition, and there was nothing that I could
do to help him.
“‘Dr. Lazear left a wife and two young children, one
of whom he had never seen.”
These experiments and many others like them
conducted on soldiers and Spanish immigrants
proved that this particular mosquito would trans-
mit the disease under certain conditions.
1. The mosquito must bite the patient during
the first three days of the fever; after that a yellow
fever patient cannot infect a mosquito.
2. A period of twelve days must elapse before
the mosquito is able to infect another person.
After that she may infect anyone she may bite;
that is, the germs remain virulent during the rest
of the mosquito’s life. The French Yellow Fever
Commission working in Rio de Janeiro claim that
the first generation of offspring from such an in-
fected mosquito is capable of causing the disease
after they are fourteen days in the adult condition.
The next step was to ascertain whether the dis-
ease could be contracted in any other way than by
the bites of infected mosquitoes. A camp named
Camp Lazear was established and the following
tests made: A mosquito-proof building of one room
128 Insects and Disease
was completely divided by a wire screen from floor
to ceiling. In one room fifteen mosquitoes that
had previously bitten yellow fever patients and had
undergone the proper period of incubation were
liberated. In this room a non-immune exposed
himself so that he was bitten by several of the in-
sects. A little later the same day and again the
next day the mosquitoes were allowed to feed on
him for a few minutes. Five days later, the usual
incubation period, he developed yellow fever.
At the same time that he entered the building
two other non-immunes entered the other compart-
ment where they slept for eighteen nights separated
from the mosquitoes by the wire screen. They
showed no signs of taking the fever. |
In another mosquito-proof house two soldiers
and a surgeon, all non-immunes, lived for twenty-
one days. From time to time they were supplied
with soiled articles of bedding, clothing, etc., di-
rect from the yellow fever hospital in the city.
These articles had been soiled by the urine, fecal
matter and black vomit obtained from fatal and
other cases of yellow fever. These articles were
handled and shaken daily, but no disease developed
among the men and at the end of the twenty-one
days, two other non-immunes relieved them and
handled a new supply of clothing in the same way,
Mosquitoes and Yellow Fever — 129
sleeping between the same sheets that had been
used by a patient dying of yellow fever and expos-
ing themselves in every possible way to the soiled
clothing. But no disease developed. ‘That these
men were susceptible was shown later by inocu-
lating some of them, when they developed the
disease.
In another experiment certain men in a camp
allowed themselves to be bitten by mosquitoes that
had passed through the proper period of incuba-
tion and every one of them and no others con-
tracted the disease. It was also shown that a mos-
quito was capable of communicating the disease
as long as fifty-seven days after it had bitten a
yellow fever patient. Another set of experiments
showed that a subcutaneous injection into a non-
immune of a very small quantity of blood from the
veins of a yellow fever patient in the first two or
three days of the disease would produce the fever.
SUMMARY OF RESULTS
Since that time much other work has been done
by independent workers as well as by French and
English Commissions both working at Rio de
Janiero. The results of their investigation are
practically the same and may be summed up as
follows:
130 Insects and Disease
1. The virus of the yellow fever is in the blood-
plasma, not in the corpuscles, for these may be re-
moved and the plasma still be infective.
2. The virus is conveyed from one patient to an-
other by the yellow fever mosquito, Stegomyia
calopus, and in no other way except by experi-
mental injections.
3. The patient is a source of infection only dur-
ing the first three or four days of the disease (this
after the three to six days of incubation).
4. The virus must undergo an incubation period
of twelve to fourteen days in the mosquito before
she is capable of transmitting the disease.
5. The parasite, whatever it is, has never been
seen. It is probably too small to be seen by any
of our present microscopes, even the recently in-
vented ultramicroscope. It is probably not a bac-
terial parasite but very likely a Protozoan, and cer-
tain specialists have even shown by the study of
all the available data that it almost certainly be-
longs to the Sporozoan genus Spirocheta.
Now what does all this mean? It means the
saving of hundreds of human lives annually. It
means the banishing from many localities and
possibly very soon from the face of the earth of a
disease that since the earliest settlements on this
continent has been a source of terror. It means
are
Mosquitoes and Yellow Fever 131
the making habitable of certain places which here-
tofore a white man has entered only at the risk of
his life. It means that quarantines need no longer
be established when yellow fever breaks out in a
district; quarantines which have inevitably caused
the loss of millions of dollars to the world of com-
merce.
RESULTS IN HAVANA
The first practical work based on these findings
was done in Havana. The Yellow Fever Commis-
sion made their recommendations in 1900. In
1go1 and 1902 they were put into effect. The fol-
lowing table of the death rate there during a period
of ten years shows graphically the results:
DEATHS IN HAVANA FROM YELLOW FEVER
1893 | 1894| 1895 | 1896 | 1897 | 1898 | 1899 | Ig00 | IgQOI | 1902
Jan. 15 aay eS.) LOGO 7 I 8 "| °
Feb. 6 4 4 7 24 I fo) 9 5 fo)
Mar 4 2 2 ce iawi Te) 2 I 4 I oO
Apr. 8 4 64 ral oa I 2 ol o °
May 22 TOC TOW 27) So 4 fe) 2 fo) fe)
June 69} 31 16{| 46] 174 3 I 8 ° fo)
July 15) 77 88 | 1x6] 168) 16 2.) 30 I fe)
Aug Heo |) 731 T20|)262)' 102) 16) 13|.. 49 2 fe)
Sep Boy 70) 135) O07, 561) 34) 1B) 52 2 °
Oct ATi aO)| TO2| 240)" 42}, 261) 251) a4 fo) fo)
Nov ON 2a a5 24a 26.0 131) rs |) 64 fo) °
Dec BD hy 20 |) 20s) T47 Sh IZ een Leo fo) fo)
132 Insects and Disease
As long as the United States held control at
Havana the yellow fever was kept in check by
fighting the mosquitoes, when this vigilance was
relaxed the fever began to appear again and the
Cubans found that it was necessary to keep up the
fight against the mosquitoes if the island was to be
kept free from the disease.
THE FIGHT IN NEW ORLEANS
In the summer of 1905 came another oppor-
tunity to put the knowledge gained during these
experiments to a practical test. Samuel Hopkins
Adams in his article in McClure’s Magazine,
June, 1906, says of the beginning of this fight:
“Eight years before, the mosquito-plague had in-
fected the great, busy, joyous metropolis of the south.
Ignorant of the real processes of the infection, New
Orleans had fought it blindly, frantically, in an agony
of panic, and when at last the frost put an end to the
helpless city’s plight, she lay spent and prostrate. The
yellow fever of 1905 came with a more formidable and
unexpected suddenness than that of 1897. It sprang
into life like a secret and armed uprising in the midst
of the city, full-fledged and terrible.. But there arose
against it the trained fighting line of scientific knowl-
edge. Accepting, with a fine courage of faith that
most important preventive discovery since vaccination,
eee eee eet
Mosquitoes and Yellow Fever 133
the mosquito dogma, the Crescent City marshaled her
defenses. ‘This time there was no panic, no mob-rule
of terrified thousands, no mad rushing from stunned
inertia to wildly impractical action; but instead the
enlistment of the whole city in an army of sanitation.
Every citizen became a soldier of the public health.
And when, long before the plague-killing frost came,
the battle was over, New Orleans had triumphed not
only in the most brilliant hygienic victory ever achieved
in America, but in a principle for which the whole
nation owes her a debt of gratitude.”
For some time the authorities had been trying
to keep secret the fact that the disease was preva-
lent, but the rapidity with which it spread made
them realize that only united action on the part of
all the community would be of any avail. The
Citizens Volunteer Ward Organizations were or-
ganized for the purpose of fighting the mosqui-
toes which were everywhere. ‘To many the fight
looked hopeless. ‘The miles of open gutters, the
thousands of cisterns and little pools of standing
water everywhere furnished abundant breeding-
places for the mosquitoes. ‘The ditches and ponds
were drained or salted, the cisterns were screened,
infected houses were fumigated, yet the fever con-
tinued tospread. Rains refilled the ditches, winds
tore the screens from the cisterns, the ignorant
134 Insects and Disease
people of the French quarter refused to codperate.
At last the city in desperation appealed to the
President for aid. Surgeon J. H. White and a
number of officers and men of the United States
Public Health and Marine Hospital Service soon
took charge of the work. ‘This was continued
along the same lines as before with the same ob-
ject in view. But with the coming of the regulars
the work was more systematically and thoroughly
done. Every case of fever was treated as though
it was yellow fever and every precaution taken
to prevent mosquitoes from biting such a patient.
The houses in which the fever occurred were
thoroughly fumigated to kill any mosquitoes that
might be there, and the neighborhood was thor-
oughly searched to find any places where the mos-
quitoes might be breeding. So confident were the
authorities that the mosquito was the sole cause of
the disease spreading, that besides fighting it no
other work was undertaken save to make the sick
as comfortable as possible.
Finally the results began to be apparent. The
number of cases gradually diminished, until long
before frost came the city was free from the great
pest. Yellow fever will doubtless appear from
time to time in New Orleans and other cities, but
there is, at least there should be, small danger of
Mosquitoes and Yellow Fever 135
another great epidemic, for the people now know
how the disease is caused and the remedy.
Not long since I had occasion to write to a
prominent entomologist in Louisiana for some
specimens of the yellow fever mosquito for labora-
tory work. The following extract from his reply
will show something of the work that is still being
done there.
“T am afraid we cannot furnish specimens of Steg-
omyia, in spite of the fact that Louisiana is supposed
to be the most favorable home of this species in the
South. Since the light occurrence of yellow fever in
this State in 1905, a very vigorous war has been kept
up against Stegomyia, and the ordinances of all Louis-
lana cities and principal towns require the draining
of all breeding places of this mosquito and the constant
oiling or screening of all cisterns or other water con-
tainers. The result is this species is very rare. Here
in Baton Rouge I only see one once in a great while,
and it would require perhaps a good many days’ work
at the present season to get as good specimens and as
many of them as you require.”
IN THE PANAMA CANAL ZONE
Yellow fever was one of the worst obstacles that
confronted the French when they were attempting
to build the Panama Canal. The story of the
136 Insects and Disease
suffering and death from this dread disease there
is most pathetic. Ship-load after ship-load of
laborers were sent over, as those who had gone
earlier succumbed to the fever. The contractors
were responsible for their men while they were
sick and in order to avoid having to pay hospital
expenses the men were often discharged as soon
as they showed signs of sickness. Many of them
died along the roadside while endeavoring to
reach some place where they could obtain aid.
The hospitals were usually filled with yellow fever
patients, a very large percentage of whom died.
Not only the day laborers suffered but many of
the engineers, doctors, nurses and others sickened
and died of the disease. It is reported that eighteen
young French engineers came over on one vessel
and in a month after their arrival all but one had
died of the yellow fever. Out of thirty-six nurses
brought over at one time, twenty-four died of the
fever, and during one month nine members of the
medical staff of one of the hospitals succumbed.
One of the first things that the United States
Government did in beginning work in the canal
zone was to take up the fight against the yellow
fever mosquito. In Panama where the water for
domestic purposes was kept in cisterns and water-
barrels, inspectors were appointed to see that all
Mosquitoes and Yellow Fever 137
such receptacles and other possible breeding-places
for mosquitoes were kept covered. After the first
inspection, 4,000 breeding-places were reported.
About six months later there were less than 4oo.
Similar work was done in all the towns and settle-
ments along the route of the canal. In addition to
this fight against the yellow fever mosquito con-
siderable attention was paid to the breeding-places
of the malarial mosquito. The results have been
remarkable. Cases of yellow fever are now rare
throughout this zone, and there has been a very
great reduction in the extent of the malarial dis-
tricts. ‘The last case of yellow fever occurred in
May, 1906. Before this work was done a man took
his life in his hands when he went into this region.
Now it is regarded as a perfectly safe place to live.
Indeed it is a much safer place than many sections
of our own country where proper sanitary measures
have not been taken to protect the health of the
community.
IN RIO DE JANEIRO
In Rio de Janeiro they have as yet been unable to
get rid of the mosquitoes, although thousands of
dollars are spent annually in fighting them. But
the non-immunes there protect themselves by do-
ing their business in Rio during the day and going
back at night to Petropolis, twenty-five miles in-
138 Insects and Disease.
land and twenty-five hundred feet higher, where
they are safe, for no Stegomyia have ever been
found there.
They claim there that the yellow fever mosquito
does not bite during the daytime after she has
laid her eggs, and that she will not lay her eggs un-
til about three days after she has fed on blood,
therefore a Stegomyia that bites during the day
will not carry the yellow fever because she is too
young. ‘This seems to explain why the fever can-
not be contracted by being bitten by a mosquito
in the daytime. Certain other experiments, how-
ever, have given different results so that as far as
we know it is not safe to be bitten at any time by
such a mosquito in a region where the disease is
endemic or where it is epidemic.
In the main the work of the French Yellow
Fever Commission working in Rio de Janiero has
confirmed the findings of the American Com-
mission. One interesting special thing that the
French Commission seems to have established is
that the female may transmit the infecting power
to her offspring, so that it would be possible for
a mosquito that had never bitten a yellow fever
patient to be capable of infecting a non-immune
person. While all this is very probable in the light
of what we know of the disease and the way in
Mosquitoes and Yellow Fever 139
which other diseases caused by similar organisms
may be transmitted by the parent to the offspring,
yet the most conservative investigators are waiting
for further proof.
HABITS OF STEGOMYIA
The whole fight against yellow fever, then is
directed, as we have seen, against the mosquito,
Stegomyia calopus. ‘The habits of this species
are such as to make it easy in some respects to
combat. It is seldom found far away from human
habitation. The adults will not fly far. Once ina
house they usually stay there except when they
leave to deposit their eggs.
On the other hand, some of these same habits
make it all the more dangerous. It will breed in
almost any kind of water, no matter how filthy, and
a very small amount will suffice. ‘Thus any leaks
from water-pipes or drains, cisterns, small cans of
water or any such places may become dangerous
breeding-places. If conditions are unfavorable
there will often be developed small individuals
which can easily make their way through ordinary
mosquito-netting.
Dr. Manson has pointed out an interesting
possible result of the crusade that is now being
waged against the yellow fever mosquitoes. The
140 Insects and Disease
immunity of the people native to the endemic
regions is supposed to be due to their having had
mild attacks of the fever during childhood, for the
children in these regions are subject to certain
fevers which are probably very mild forms of
yellow fever.
Now if we kill practically all of the Stegomya
so that these children do not have this fever there
will be developed, in due time, a population most
of whom are non-immune.
This freedom from the disease for some time
will allow us to grow careless in regard to fighting
the mosquitoes. ‘They will be allowed to increase
and by some chance the yellow fever will again be
introduced and there will then be very grave danger
of most extensive and destructive epidemics.
DANGER OF THE DISEASE IN THE PACIFIC
ISLANDS |
I have already referred once or twice to the con-
ditions in many of the Pacific tropical islands. ©
In some of these various species of Stegomyza are
abundant, and in some Stegomyia calopus is the
most abundant and troublesome form. All the
natives of these islands are non-immune because
there has never been any yellow fever there. Un-
less extraordinary care is taken the disease will be
Mosquitoes and Yellow Fever 141
introduced there sooner or later and the results
are sure to be most appalling. The climatic and
sanitary conditions and the habits of the people are
ideal for the development and spread of the disease,
and what I have seen of the conditions on some of
these islands convinces me that it would be almost
impossible to control the disease before it had a
chance to kill a large percentage of the population.
With the opening of the Panama Canal these
things become more possible. Heretofore, the
shipping to these regions has not been from ports
where yellow fever was endemic or even likely to be
epidemic. But unless the yellow fever is kept out
of the canal zone, the danger will be many fold what
it is now.
The white man has already carried enough
misery to these island peoples in the way of loath-
some diseases, and it is to be hoped that this, an-
other great curse, will not be carried to them with
our civilization, the beneficial results of which
have been so often very justly questioned.
What I have said in regard to these islands ap-
plies with equal force and in some instances with
even greater force to parts of Asia, the Eastern
Archipelago and other places.
CHAPTER IX
FLEAS AND PLAGUE
wi] LAGUE has always been one of the most
| dreaded diseases, and when we read of
its ravages in the old world and the
utter helplessness of the people before
it we do not wonder that the very word filled them
with horror. One of the greatest scourges ever
known began in Egypt about A. D. 542, and spread
along the shores of the Mediterranean to Europe
and Asia. It lasted for sixty years, appearing again
and again in the same place and decimating whole
communities.
Another great pandemic, beginning in 1364,
spread over the whole of the then known world and
appeared in its most virulent form. On account
of diffuse subcutaneous hemorrhages it came to be
known as the “‘black death” and of course spread
terror in all the communities where it appeared.
Whole villages and districts were depopulated.
The death-rate was very high, one authority placing
the total mortality at twenty-five million.
142
a
Fleas and Plague 143
During this time new centers of infection were
established, and since then it has been carried by
the commerce of the nations to all parts of the
world. It is not restricted, as many other epidemic
diseases, to the tropics or semi-tropics, although as
a matter of fact we find it is more prevalent in these
regions on account of the sanitary conditions.
HOW PLAGUE WAS CONTROLLED IN SAN
FRANCISCO
Attention is called to these things in order that
we may compare past conditions with present.
During the last few years San Francisco has been
fighting an outbreak of plague that in other days
would have been nothing less than a national
calamity. But with modern methods of handling
it, based on knowing what it is, what causes it and
how it is spread, the authorities there have been
able not only to hold the disease in check, but
practically to stamp it out with the loss of com-
paratively few lives.
Dr. Blue of the Public Health and Marine Hos-
pital Service and his co-workers directed their
whole energy toward controlling the rats. A small
army of men were employed, catching rats in
every quarter of the city. Dr. Rucker reports that
fully a million rats were slain in this campaign.
144 Insects and Disease
Their breeding-places were destroyed by making
cellars, woodsheds, warehouses, etc., rat-proof and
removing all old rubbish. Garbage cans were in-
stalled in all parts of the city, as it was required
that all garbage be stored where rats could not feed
upon it, and altogether every effort was made to
make it as uncomfortable as possible for the rats.
The marked success attending this work abun-
dantly confirms the soundness of the theory upon
which it was based, and serves as another example
of the way in which science is teaching us how to
prevent or control many of our most serious dis-
eases. 3
THE INDIAN PLAGUE COMMISSION
In 1896, what proved to be a very serious out-
break of plague, occurred in Bombay and spread
to other parts of India. In 1898, a commission
was appointed to inquire into the origin of the dif-
ferent outbreaks, the manner in which the disease
is communicated, etc. This was known as the
Indian Plague Commission, and its exhaustive re-
port, together with the minutes of the evidence
presented to the committee, represents a stupen-
dous amount of work on this subject and is the
basis for much of the later investigation that has
been undertaken.
Fleas and Plague 145
After the consideration of the evidence from
various sources the commission decided that the
principal mode of infection both for man and rats
was through some sort of an abrasion in the skin,
although it recognized also the possibility of in-
fection through the nose and throat, and possibly,
very rarely, through the intestinal tract or other
places.
Considerable time was spent in considering Dr.
Simond’s claim, made in 1898, that fleas which
have been parasitic on plague-infected rats migrate
on the death of their hosts and convey the infection
to healthy men and rats. Dr. Simond sought to
establish the following:
“Firstly, that plague rats are eminently infective
when infected with fleas and that they cease to be in-
fective when they have been deserted by their parasites:
Secondly, that living plague bacilli are found in asso-
ciation with fleas which are taken from plague-infected
rats: Thirdly, that plague can pass from infected rats
to other animals which have not come directly in
contact with them or with their infected excretions:
Fourthly, that fleas which infest rats will transfer
themselves as parasites to men.”
After reviewing the experiments which had been
made to establish these claims the commission be-
lieved that sufficient precaution had not been
146 Insects and Disease
taken to prevent infection from other sources and
that not enough definite evidence was produced.
Against this claim much negative evidence was
considered and the final conclusion was ‘‘that suc-
torial insects do not come under consideration in
connection with the spread of plague.”
In 1905 another body of men known as the Ad-
visory Committee was appointed to arrange for
further studies in India and other places, particu-
larly in relation to the mode of dissemination of the
disease. They at once appointed a new working
commission who immediately began their studies
and experiments. The preliminary reports of their
work, which are still known as the Reports of the
Indian Plague Commission, as well as the reports
of contributing investigations that are being made
from time to time, have served to establish entirely
Dr. Simond’s claims and have completely revolu-
tionized the methods of fighting plague.
There are several different types of plague, seem-
ing to depend largely on the manner of infection.
The most common type is that known as the bu-
bonic plague which is characterized by buboes or
swellings in various parts of the body. This form
of infection is usually received through the skin
in some manner or other. Only rarely does direct
man-to-man infection occur though there is always
Fleas and Plague 147
the possibility of it. The investigations have
shown that the flea is the most common agent in
transferring the disease from rat to rat or from rat
to man. This may be accomplished by the flea
transferring the bacilli directly from one host to an-
other on its proboscis, or they may be carried in the
alimentary canal of the flea and gain an entrance
into the skin through an abrasion of some kind
when the flea is crushed as it is biting, or when some
of the bacilli are left on the skin in the excreta of the
insect.
RESULTS OF VERJBITSKI’S EXPERIMENTS
A very important series of experiments bearing
directly on this subject was made in 1902 and 1903
by Dr. D. T. Verjbitski. The paper giving the
results of this work was not published in any
scientific journal until 1908 when the Advisory
Committee published it in one of their reports.
The experiments were so well planned and exe-
cuted and the results so definite that I think it is
worth while to give in full his summary of results.
The bugs referred to are bedbugs.
**(1) All fleas and bugs which have sucked the blood
of animals dying from plague contain plague microbes.
“‘(2) Fleas and bugs which have sucked the blood
of animals which are suffering from plague only con-
148 Insects and Disease
tain plague microbes when the bites have been inflicted
from 12 to 26 hours before the death of the animals,
that is, during that period of their illness when their
blood contains plague bacilli.
(3) The vitality and virulence of the plague mi-
crobes are preserved in these insects.
(4) Plague bacilli may be found in fleas from four
to six days after they have sucked the blood of an
animal dying with plague. In bugs, not previously
starved or starved only for a short time (one to seven
days), the plague microbes disappear on the third day;
in those that have been starved for four to four and one-
half months, after eight or nine days.
‘“‘(5) The numbers of plague microbes in the in-
fected fleas and bugs increase during the first few days.
‘“‘(6) The feces of infected fleas and bugs contain
virulent plague microbes as long as they persist in the
alimentary canal of these insects.
‘“*(7) Animals could not be infected by the bites of
fleas and bugs which had been infected by animals
whose own infection had been occasioned by a culture
of small virulence, notwithstanding the fact that the
insects may be found to contain abundant plague mi-
crobes.
‘“‘(8) Fleas and bugs that have fed upon animals
which have been infected by cultures of high virulence
convey infection by means of bites, and the more
certainly so the more virulent the culture with which
the first animal was inoculated.
Fleas and Plague 149
““(g) The local inflammatory reaction in animals
which have died from plague occasioned by the bites
of infected insects is either very slight or absent. In
the latter case it is only by the situation of the pri-
mary bubo that one can approximately identify the
area through which the plague infection entered the
organism.
‘“‘(10) Infected fleas communicate the disease to
healthy animals for three days after infection. Infected
bugs have the power of doing so for five days.
“‘(11) It was not found possible for more than two
animals to be infected by the bites of the same bugs.
“‘(12) The crushing of infected bugs in situ during
the process of biting, occasioned in the majority of
cases the infection of the healthy animal with plague.
“‘(13) The injury to the skin occasioned by the bite
of bugs or fleas offers a channel through which the
plague microbes can easily enter the body and occasion
death from plague.
‘“‘(74) Crushed infected bugs and fleas and their
feces, like other plague material, can infect through
the small punctures of the skin caused by the bites of
bugs and fleas, but only for a short time after the in-
fliction of these bites.
“‘(15) In the case of linen and other fabrics soiled
by crushing infected fleas and bugs on them, or by the
feeces of these insects the plague microbes can under
favorable conditions remain alive and virulent during
more than five months.
150 Insects aud Disease
(16) Chemical disinfectants do not in the ordinary
course of application kill plague microbes in infected
fleas and bugs.
““(77) Therat flea Typhlopsylla musculi does not bite
human beings.
“‘(18) Human fleas do bite rats.
‘‘(19) Fleas found on dogs and cats bite both hu-
man beings and rats.
‘‘(20) Human fleas and fleas found on cats and dogs
can live on rats as casual parasites, and therefore can
under certain conditions play a part in the transmis-
sion of plague from rats to human beings, and vice
versa.”
RESULTS OF VARIOUS INVESTIGATIONS
Various other plague commissions from other
countries as well as many individuals have in-
vestigated the same subject, and the results all
point conclusively to the fact that the rats and the
fleas are at least the most important factors in the
spread of the disease. The evidence from many
sources and from many experiments may be briefly
summed up as follows: The disease is caused by
the presence in the system of minute bacteria,
Bacillus pestis. It is probable that plague is pri-
marily a disease of rats and only secondarily and
accidentally, as it were, a disease of man.
Rats are subject to the plague and are often
Fleas and Plague 151
killed by it in great numbers. An outbreak of
plague among men is often preceded by a very
noticeable outbreak among rats.
Rats dying of the plague have their blood filled
with the plague bacillus. Fleas or other suctorial
insects feeding on such rats take myriads of these
bacilli into their stomach and get many on their
proboscis.
The fleas usually leave a rat as soon as it dies
and of course seek some other source of food.
When such infected fleas are permitted to bite other
rats or guinea-pigs these animals often develop the
disease. Several of the species of fleas that infest
rats will bite man also, and in the cases of many
plague patients it can be definitely shown that they
had recently been bitten by fleas.
STRUCTURE AND HABITS OF FLEAS
A study of the structure and habits of fleas shows
that in many respects they are particularly adapted
for spreading such a disease as bubonic plague.
The piercing proboscis consists of three long needle-
like organs, the epipharynx and mandibles, and a
lower lip or labium. The mandibles have the sides
serrate like a two-edged saw. The labium is di-
vided close to its base so that it really consists of
two slender four-segmented organs which lie close
152 Insects and Disease
together and form a groove in which the piercing
organs lie. When the flea is feeding, the epi-
pharynx and mandibles are thrust into the skin ©
of the victim, the labium serving as a guide. As
the sharp cutting organs are thrust deeper and
deeper the labium doubles back like a bow and
does not enter the skin. Saliva is then poured into
the wound through minute grooves in the mandi-
bles, and the blood is sucked up into the mouth by
the sucking organ which lies in the head at the
base of the mouth-parts. Just above this piercing
proboscis is a pair of flat, obtuse, somewhat tri-
angular pieces, the maxillary blades or maxille.
When the proboscis is fully inserted into the skin
the tips of these maxille may also be embedded in
the tissue and perhaps help to make the wound
larger. Attached to these maxille is a pair of
rather stout, four-jointed appendages, the palpi.
They probably act as feelers.
If the flea chances to be feeding on a plague-
infected rat or person many of the plague bacilli will
get on the mouth-parts and myriads of them are of
course sucked up into the stomach with the blood.
Those on the proboscis may be transferred directly
to the next victim that it is thrust into, and those in
the stomach may be carried for some time and
finally liberated when the flea is feeding again or
I'ic. 1c6—Rat-flea (L. cheopis); female.
é
Af
-
oe
ae te
Fic. 108—Human-flea (Pulex irriians); male,
Fleas and Plague 153
when it is crushed by the annoyed host. ‘The
latter is probably the most common method of in-
fection, for the bacilli that are liberated when the
flea is crushed may readily be rubbed into the
wound made by the flea bite or into abrasions of
the skin due to the scratching. Kill the flea, but
don’t ‘‘rub it in.”
During the recent outbreak in San Francisco
many thousand fleas that were infesting man, rats,
mice, cats, and dogs, squirrels and other animals
have been studied and it has been found that while
each flea species has its particular host upon which
it is principally found, few if any of them will hes-
itate to leave this host when it is dead and attack
man or any other animal that may be convenient.
COMMON SPECIES OF FLEAS
Throughout India and in all the warm climates
where plague frequently occurs the most common
flea found on rats has come to be known as the
plague flea (Lemopsylla cheopus) (Figs. 105, 106),
and is doubtless the principal species that is con-
cerned in carrying the disease in those climates.
It now occurs quite commonly on the rats in the
San Francisco Bay region and is occasionally
found there on man also. In the United States,
Great Britain and other temperate regions another
154 Insects and Disease
larger species, Ceratophyllus jasciatus is by far
the most common flea found on rats, and is com-
monly known as the rat flea. It occurs on both
the brown and the black rats Mus norvegicus and
M. rattus, on the house mouse and frequently on
man. It has also been taken in California on
pocket gophers and on a skunk.
The common human flea (Pulex «rritans)
(Figs. 108, 109), is found in all parts of the in-
habited world. Although we regard it primarily
as a pest of human beings it often occurs very
abundantly on cats, dogs, mice and rats as well as
on some wild mammals such as badgers, foxes and
others and has occasionally been found on birds.
Most entomologists regard the fleas commonly
found on cats and dogs as belonging to one species
Ctenocephalus canis. Others believe them to be
distinct species and call the cat flea Ctenocephalus
jelis. So far as our personal comfort and safety
is concerned it makes but little difference to us
whether the flea that bites us is called canis or jelis
for they both look very much alike, and act alike
and the bite of one hurts just as much as the bite
of the other. Although cats and dogs are their nor-
mal hosts they are very often troublesome house-
hold pests, sometimes making a house almost un-
inhabitable. They are frequently found on rats,
Fleas and Plague 155
and therefore may carry the plague bacillus from
rat to rat or from rat to man.
GROUND-SQUIRRELS AND PLAGUE
As early as 1903 Dr. Blue, in charge of the plague
suppressive measures in San Francisco, became im-
pressed with the possibility of the common Cali-
fornia ground-squirrels (Otospermophilus beecheyt),
acting as an agent in the transmission of plague.
It was rumored at that time that some epidemic
disease was killing the squirrels in some of the
counties surrounding San Francisco Bay, notably
in Contra Costa County. None of the squirrels
were examined at that time, but since then many
thousand have been carefully studied and it has
been definitely shown that many of them are plague-
infected. Just how the plague got started among
them will probably never be really known. There
is little doubt, however, but that it was transferred
in some way from the rats to the squirrels. The
trains and the bay and river steamers running out
from San Francisco would afford abundant oppor-
tunity for the rats to go from the city to the ware-
houses all along the shore. Once there they would
use the same runways as the squirrels about the
warehouses and in the near-by fields. In harvest
time the rats migrate to the fields and make con-
156 Insects and Disease
stant use of the squirrel holes. The farmers in
some sections report that they frequently catch
more rats than squirrels in traps set in squirrel
holes at that season of the year.
This close association of the rats and the squir-
rels affords a good opportunity for the fleas infest-
ing them to pass from one host to the other. |
So far only two species of fleas have been re-
corded from the ground-squirrels. One, Cerato-
phyllus acutus, is very common, sometimes literally —
swarming over the squirrels, particularly if a squir-
rel is sick or weak from any cause. The other spe-
cies, Hoplopsyllus anomalus, is less abundant but
still quite common. Both of these species infest
rats also, so the chain of evidence is practically
complete. We have only to assume that at some-
time one or more of the plague-infected rats found
their way into the region where the squirrels were,
and the fleas passing from the rats to the squirrels
would carry the plague with them.
The fact that the plague already has such a start
among the squirrels opens a new and very serious
phase of the problem of suppressing the disease.
All who have hunted the ground-squirrels will
testify to the readiness with which the fleas from
them will bite those who are handling them. As it
is the sick or weak squirrels that are most often
Fic. 1og—Human-flea (P. irritans); female.
Fic. 1r0—Mouse-flea (Cienopsyllus musculi); female.
Fleas and Plague 157
taken there is always a chance that plague may be
transferred from them to human beings. The
records of the plague cases in California show at
least three cases in which there seems to be very
little doubt that the disease resulted from handling
plague-infected squirrels.
A still more serious thing is the possibility of the
disease remaining in a more or less virulent form
among the squirrels for some time, possibly for
years, and then breaking out again in some locality
where the rats or men may become infected. As
long as there is a trace of the disease among the
squirrels there is always the chance of it spreading,
so that new areas may become infested. Those in
charge of the plague-suppressive measures are fully
aware of these dangers and are making a careful
study of the situation and will doubtless be able
to cope with it successfully. It may be that the
squirrels will have to be exterminated in the in-
fected regions. ‘This would be a long and difficult
task, but the success attending the fight against the
rats in a great city shows what can be done when
the determination to do it is there.
REMEDIES FOR FLEAS
We have seen how a great city set to work to rid
itself of the plague-sick rats. As a matter of fact
158 Insects and Disease
it was not the rats that they were after primarily.
If the rats had not harbored fleas the city would
have been glad to let the disease take its course and
destroy as many rats as possible. But it was found
that the only way to get rid of the fleas that might
possibly be infected with the plague was to kill
their rat hosts.
General cleaning-up measures will of course
very materially lessen the number of fleas about the
private dwellings, but there often remains a num-
ber of fleas in the house that are a source of great
annoyance even if the danger is eliminated.
Particularly is this apt to be so in places where
cats or dogs are members of the household. These
animals almost always harbor at least a few fleas,
and where there are a few there is always a possi-
bility, even a great probability, that there will be
many more unless an effort is made to get rid of
them.
In some sections of the country it is the cat and
dog flea that is the most troublesome to man. The
minute white eggs of the fleas are usually laid about
the sleeping-places of these animals and the slender
active larve that hatch from them feed upon any
kind of organic matter that they can find in the
dust or in the cracks and crevices. About eight or
ten days after hatching the larve spin delicate
Fleas and Plague 159
brownish cocoons in which they pass the pupal
stage, issuing a few days later as the adult fleas.
It will at once appear, then, that it is important
to provide the cats and dogs with sleeping-places
that can be kept clean. If they have a mat or
blanket to sleep on this can be taken up and
shaken frequently and the dust swept up and
burned. In this way many of the eggs or larve
may be destroyed. Very often the dust under a
carpet that has not been taken up and dusted for
some time will be found to be harboring a mul-
titude of fleas or their larve. In such cases a
thorough cleaning of the carpet and the floors will
bring relief. Houses that are unused for some time
during the summer months are often found to be
overrun with fleas in the fall, for the fleas have had
an unmolested opportunity to breed and multiply.
Such rooms of course require a thorough cleaning
or it is sometimes possible to kill the fleas by a lib-
eral use of pyrethrum powder or benzine or to
fumigate. In this connection, Dr. Skinner’s note
in the Journal of Economic Entomology is worth
repeating.
“In the latter part of last May (1908) I moved into a
house that had not been previously occupied. No car-
pet was used and being summer only a few rugs were
placed on the floors. A part of the household consisted
160 Insects and Disease
of a collie dog and three Persian cats.. Very soon the
fleas appeared, the dog and cat flea, Ctenocephalus
canis. I did not count them and I can’t say whether
they numbered a million or only a hundred thousand.
On arising in the morning and stepping on the floor
one would find from three to a dozen on the ankles.
The usual remedies for fleas are either drastic or some-
what unsatisfactory. The drastic one is to send the
animals to the institutions, where they are asphyxiated,
or take the other advice, ‘Don’t keep animals.’
“T tried mopping the floors with rather a strong
solution of creolin but it did little good. Previous
experience with pyrethrum was not very satisfactory.
Knowing the volatility of naphthalene in warm weather
and the irritating character of its vapor led me to try
it. I took one room at a time, scattered on the floor
five pounds of flake naphthalene and closed it for
twenty-four hours. On entering such a room the
naphthalene vapor will instantly bring tears to the eyes
and cause coughing and irritation of the air passages.
I mention this to show how it acts on the fleas. It
proved to be a perfect and effectual remedy and very
inexpensive, as the naphthalene could be swept up and
transferred to other rooms. So far as I am concerned
the flea question is solved and if I have further trouble
I know the remedy. I intend to keep the dog and the
cats.”
CHAPTER X
OTHER DISEASES, MOSTLY TROPICAL,
KNOWN OR THOUGHT TO BE TRANS-
MITTED BY INSECTS
SLEEPING SICKNESS
NE of the worst scourges of Africa and
Mi one that is to-day attracting world-
wide attention is the disease known as
trypanosomiasis, the terminal phase of
which is sleeping sickness, one of the most ghastly
diseases that we know.
Among the Protozoa referred to in one of the
earlier chapters mention was made of certain try-
panosomes which inhabit the blood of man and
certain animals. Very little was known concerning
these parasites previous to the beginning of the
present century, but since that time several have
been found to be of great economic importance.
The group is being studied extensively and every
day our knowledge of them is increasing so that
we now know quite definitely the life-history of
several.
161
162 Insects and Disease
Trypanosoma lewisi, a parasite of rats, is per-
haps the best known as it is always common where-
ever rats are found. Sometimes as many as 30% or
40% of the rats of certain districts are infected.
It is thought that these are transmitted from rat to
rat by the common rat-louse which serves as an
intermediate host. Fleas may also act as dissem-
inating agents.
A few other kinds cause serious disease of ani-
mals, but we are more interested just now in the
particular one that is causing so much trouble in
Africa. ‘This parasite was discovered in 1902 and
was named Trypanosoma gambiensi (Fig. 111).
Since then it has been found to be widely dis-
tributed. Although the natives have doubtless long
been subject to the disease caused by this parasite,
the recent influx of whites to these regions and
the consequent movements of the natives have
caused a great spread of the disease so that whole
regions are now made desolate, the inhabitants
dying or fleeing to escape the uncanny death.
The disease may run its course in a few months
or it may take years. ‘The symptoms are various,
but infection is usually soon followed by fevers,
sometimes mild, sometimes severe, which recur at
irregular intervals. Certain glands or other parts
of the body may become swollen. More or less
Other Diseases Transmitted by Insects 163
extensive skin eruptions occur on all parts of the
body and the patient gradually becomes anemic
and physically and intellectually feeble. The
nervous system seems to be affected by the para-
site, either directly or by the action of the toxins
it produces. ‘The patient becomes more debili-
tated and morose with an increasing tendency
to sleep, hence the name sleeping sickness. As
the stupor deepens the patient looses all desire
or power of exertion and as little food is taken
he rapidly wastes away and finally succumbs
for after this final stage is reached there is no re-
lief.
It is definitely known that a species of tsetse-
fly, Glossina palpalis (Fig. 112), which somewhat
resembles our stable-fly, is responsible for the
dissemination of the disease, and some recent in-
vestigators have suggested that certain species of
mosquitoes may also carry the parasite from one
host to another. There still remains some doubt
as to the exact manner in which the fly transmits
the disease, but it seems altogether likely that it is
an alternative host and does not serve as a simple
mechanical carrier. In this respect it is like the
mosquito which is one of the necessary hosts of
the malaria parasites, and unlike the house-fly
which carries the germs of various diseases in a
164 Insects and Disease
purely mechanical way without serving as a definite
necessary host for the parasite.
The tsetse-fly is found only in tropical Africa
and is limited in its distribution there to certain
very definite, narrow, brushy areas along the water’s
edge. If these places can be avoided there seems
to be little danger. Those who are fighting the dis-_
ease have found that if the brush in the vicinity of
watering-places and ferry-landings is cleared away
such places become comparatively safe. These
flies do not lay eggs but produce full-grown larvee
which soon pupate in the ground.
ELEPHANTIASIS
In many tropical regions human blood as well as
that of other animals is the normal habitat of cer-
tain worm-like parasites (Nematodes). They are
not entirely confined to the tropics but may ex-
tend far up into the subtropical regions. Five or
six different species of these parasites are known,
only one of which, however, has been shown to be
of any pathological importance, as far as human
beings are concerned.
This species, Filaria bancrojtt, is not only very
widely distributed, but in regions such as some of
the South Sea Islands a very large per cent of the
natives have the filaria present in their blood.
FIG. 111—T7rypanosoma gambiense; various forms from
blood and cerebrospinal fluid. (After Manson.)
Fic. 112—Tsetse-fly. (After Manson.) .
Other Diseases Transmitted by Insects 165
When these parasites are withdrawn from the circu-
lation and placed on a slide for study they are seen
to be minute transparent, colorless, snake-like or-
ganisms inclosed in a very delicate sack or sheath.
They are but a little more than one-hundredth of
an inch long and about as big around as a red
blood-corpuscle. These are the larval forms of the
parasite and have been called by Le Dantec the
micro-filaria.
If blood of the patient drawn from the skin, is
examined during the day few if any of these para-
sites are found, but if it is examined between five
or six o’clock in the evening and eight or nine
o’clock the next morning they may be found in
numbers. During the daytime they have retired
from the peripheral circulation to the larger arter-
ies and to the lungs, where they may be found in
great numbers.
This night-swarming to the peripheral circu-
lation has been found to be a remarkable adapta-
tion in the life-history of the parasite, for it has been
demonstrated that in order to go on with its de-
velopment these larval forms must be taken into
the alimentary canal of the mosquito. Most of the
mosquitoes in which the development takes place
are night-feeders, so that the parasites are sucked
up with the blood of the victim. Once inside the
166 Insects and Disease
stomach they soon free themselves from the in-
closing sheath and make their way through the
walls of the stomach and enter the muscular tissue,
particularly the thoracic muscles. Here they un-
dergo a metamorphosis and increase enormously in
size, some attaining one-sixteenth of an inch in
length.
After sixteen to twenty days they leave these
muscles and make their way to other parts of the
body. A few may be found in different parts of the
abdomen, but most of them make their way forward
into the head of the mosquito and coil themselves
up close to the base of the proboscis, finally finding
their way down into the proboscis inside the la-
bium. Here they lie until an opportunity offers for
them to escape to the warm blood of a vertebrate.
They probably pass through the thin membrane
connecting the labella with the proboscis and there
find their way into the wound made by the punc-
ture when the insect bites. Whether these para-
sites can gain an entrance into the circulatory
system in any other way is not known. It has been
suggested that the mosquitoes dying and disinte-
grating on the surface of water may liberate the
filarie which may later find their way into the
system of the vertebrate host when the water is
used for drinking, but most of the investigations
Other Diseases Transmitted by Insects 167 °
made so far seem to indicate that they make their
way directly from the proboscis into the new host.
Soon after entering the circulatory system of the
human host the parasites make their way into the
lymphatics where they attain sexual maturity, and
in due time new generations of the larval filariz
or microfilariza are poured into the lymph, and
finally into the definite blood-vessels, ready to be
sucked up by the next mosquito that feeds on the
patient.
In most cases of infection the presence of these
filariz in the blood seems to cause no inconvenience
to the host. ‘They are probably never injurious in
the larval stage, that is, in the stage in which they
are found in the peripheral circulation.
In many cases, however, the presence of the
sexual forms in the lymphatics may cause serious
complications. ‘The most common of these is that
hideous and loathsome disease known as elephan-
tiasis in which certain parts of the patient becomes
greatly swollen and distorted. An arm or a leg
may become swollen to several times its natural
size, or other parts of the body may be seriously
affected.
In some of the South Sea Islands 30% to 40% of
the natives are afflicted in this way, some only
slightly others seriously. There is little or no pain,
168 Insects and Disease
but in severe cases the distorted parts often render
the patient entirely helpless.
The exact way in which the parasites cause such
swelling is not very definitely known. Manson,
who has done more work on these diseases than
any one else, believes that the trouble arises from
the clogging of the lymphatic glands or trunks,
thus cutting them off from the general circulation,
in which case the affected parts may become dis-
torted. ‘This clogging of the passages is believed
to be due to the presence of great numbers of im-
mature eggs which have been liberated by para-
sites injured in some way before their eggs were
entirely developed.
This interference with the lymphatic circulation
brings about the anomalous condition of a patient
with a serious filarial disease with fewer of the
filarial parasites in his blood than one who is not
so seriously affected. ‘This is supposed to be due
to the fact that the disease-producing parasites
have died and that the lymphatics have become so
obstructed that any microfilarie they may contain
cannot make their way into the general circulation.
Such a patient then would not be as likely to infect
a mosquito as would one less seriously affected.
It has always been thought that little or nothing
could be done in the way of successfully treating
re icoeans ee Fg
Other Diseases ‘Transmitted by Insects 169
this disease, but quite recently a French physician,
who has been conducting a long series of experi-
ments in the Society Islands, announced that he is
able to cure many cases by certain surgical opera-
tions on the affected parts.
DENGUE OR ‘‘ BREAKBONE FEVER ”’
This is another disease of the tropics often occur-
ring in widespread epidemics. It is probably most
frequently met with in the West Indies, but may
occur in any of the tropical countries or islands.
Occasionally it spreads into subtropical or even
temperate regions. Several extensive epidemics
have occurred in the United States. Once intro-
duced into a community it spreads very rapidly
and nothing seems to confer immunity.
The various names by which it has been called
well describe its effect on the patient; breakbone
fever, dandy-fever, stiff-necked or giraffe-fever,
boquet (or “‘bucket”’) fever, scarlatina rheumatica,
polka-fever, etc. While the suffering is intense as
long as the disease lasts it seldom terminates
fatally.
It has always been classed as a very contagious
disease and it has not yet been definitely shown
that it is not. Recent observations, however, have
shown that it is probably caused by a certain
170 Insects and Disease
Protozoan parasite that is found in the blood of
dengue patients and several experiments have been
conducted by Dr. Graham which seem to indicate
that it is transmitted by mosquitoes. In these ex-
periments, Culex jatigans, a common tropical or
subtropical mosquito, was used. ‘The same para-
site that is found in the human blood may be found
in the stomach and blood of the mosquitoes up to
the fifth day after it has fed on a dengue patient.
Sick and healthy individuals were allowed to re-
main in close contact in a room from which the
mosquitoes had been excluded, and the disease was
not spread. Mosquitoes that had bitten dengue
patients were taken to a higher region where
dengue had never occurred and allowed to bite two
healthy persons. Both developed the disease and
as they were protected from other mosquitoes until
they had recovered, the disease did not spread to
others of the community. These and other ob-
servations seem to make a complete chain of evi-
dence, and most medical men to-day accept the
theory as well proved and in their practice take
every precaution to prevent the spread of the
disease by keeping the infected patient from being
bitten by the mosquitoes.
The yellow fever mosquito is also suspected of
carrying this same disease, and it is possible that
Other Diseases ‘Transmitted by Insects 171
other species are also concerned. If it is true that
the parasite can be carried by several different
species of mosquitoes this would account very
largely for its rapid spread wherever it is intro-
duced into a community. Where it occurs outside
the tropics it is only in the warm summer months
when mosquitoes are always abundant.
MALTA OR MEDITERRANEAN FEVER
This is also a tropical and subtropical disease
that occasionally gets up into the temperate region,
sometimes occurring in the United States. The
fever begins with a severe headache, and other
symptoms follow. It is usually of the remittent
type and may continue for some months. |
It is caused by minute bacteria (Micrococcus
melitensis) and is a very infectious but not usually
contagious disease. The germ is readily conveyed
by inoculation, and several investigators have
sought to show that the mosquito often serves as
the inoculating agent. The disease is especially
prevalent during the mosquito season, and has
twice been conveyed to monkeys by infected in-
sects.
LEPROSY
This loathsome disease has long been known to
be caused by a particular bacillus (Bacillus lepre),
u72 Insects and Disease
but the way in which this organism gains an
entrance into the system is still unknown. Many
theories have been propounded, but none of them
has been well established. Within recent years
the possibility of insects carrying the germ and in
one way or another transmitting it to healthy in-
dividuals has been suggested and much discussed.
As the lepre bacilli are present in the skin and
ulcers of leprous patients, insects sucking the blood
or feeding on the sores could not help taking some
of them into their body or becoming contaminated.
These bacilli have been found at various times in
the stomach or intestine of mosquitoes, fleas and
bedbugs. So it is believed by some that these and
other insects, such as lice and flies, may sometimes
transmit the disease. On a previous page we have
referred to the possibility of the face-mites acting
as disseminators of leprosy.
Leprosy occurs most commonly among people
where little attention is paid to bodily cleanliness.
Such people are usually freely infested with various
parasites that thrive well in the filth, so if the germs
can be transmitted in this way the carriers are
there in abundance.
The fact that the sores usually occur on exposed
parts of the body has been pointed to as evidence
that inoculation is due to such insects as flies and
Other Diseases Transmitted by Insects 173
mosquitoes. It has been noted that leprosy is fre-
quently very common in regions where elephantia-
sis occurs, suggesting the possibility of the same
carrier, the mosquito, for both diseases. So while
there is as yet very little evidence one way or the
other, insects that are found around leprous pa-
tients are to be regarded with suspicion, for until
we know more definitely just how the disease is
communicated the insects must be looked on as
possible sources of contamination.
KALA-AZAR OR DUM-DUM FEVER
This is a very fatal infectious disease of many
tropical and subtropical regions, spreading terror
among the natives wherever it occurs. It is caused
by the presence in the system of Protozoan para-
sites, the so-called Leishman-Donovan bodies, that
have recently been studied by several observers.
Dr. W. S. Patton of the Indian Medical Service
has been making some extensive experiments with
the common bedbug of India (Cimex rotundatus)
which seem to demonstrate fully that this insect is
responsible for the transmission of the parasite that
causes the disease. He has found the parasite in
all stages of development in the bedbug. This,
taken with a number of other observations in re-
gard to the tendency of the disease to cling to par-
174 Insects and Disease
ticular houses, makes a strong case against the bed-
bug. Manson, however, believes that the parasite
may be transmitted by other agents also, possibly
by means of flies that visit the sores or in other
ways.
ORIENTAL SORE
This disease, once supposed to be confined to the
Orient, is now found to be rather widely distributed
throughout the tropics, where it is sometimes very
prevalent. It is caused by the presence in the
system of a parasite very similar to or identical
with the one causing kala-azar and is regarded by
some as a modified form of that disease. ‘The
patient is affected with one or more serious sores
or ulcers which usually occur on exposed parts of
the body.
The parasite that causes the disease is supposed
to be carried by insects either directly or indirectly.
In the latter case the insect may act as an inter-
mediate host. ,
Dogs and camels are also attacked by this disease
and may be sources of infection.
a
ee
BIBLIOGRAPHY
COMPLETE list of books and articles
dealing more or less directly with the sub-
jects discussed in this book would be too
extended for use here. For the past ten or
twelve years many of the medical and biological jour-
nals have contained articles in almost every issue, dis-
cussing these subjects in some of their phases. I have
selected only a few of the more important of them, and
these only the English ones, confining myself mostly to
those that I have personally consulted, and giving brief
annotations. Many of these will be found to include
very full bibliographies of the particular subject treated.
In order to avoid repetition, references are given under
one head only although many might properly be in-
cluded in other sections as well.
PARASITES AND PARASITISM
Braun, Max. Animal Parasites of Man. Translated by
Pauline Falcke and edited by L. W. Sambon and F. V. Theo-
bald. Third edition, 1906. A chapter on the general sub-
ject of parasitism and a description of parasites of all classes.
Bibliography.
LEUCKART, R. The Parasites of Man and the Diseases In-
duced by Them. Eng. transl., London, 1886.
175
176 Insects and Disease
NEUMAN, THEO. Entoparasites and Hygiene. Tvans. Vassar
Bros. Institute, VII, 1895. A general discussion of parasitism;
life-history of some common parasites that infest man.
NEUMANN, L.G. Treatise on the Parasites and Parasitic Diseases
of the Domesticated Animals. Eng. transl. by Fleming, 1892.
Ransom, B. H. How Parasites Are Transmitted. Year Book
U.S. Dept. Agric., 1905, pp. 139-166 (pub. 1906). Discusses
the ways in which parasites of all classes are transmitted.
SAMBON, L. The Part Played by Metazoan Parasites in Tropi-
cal Pathology. Jour. Trop. Med. & Hyg., Vol. XI, Jan. 15,
1908. A comprehensive discussion of this subject.
SHIPLEY, A. E., AND FEARNSIDES, E. G. Effects of Metazoan
Parasites on Their Hosts. Jour. Econom. Biology, Vol. I,
1906, pp. 41-62. Discusses injury due to mere presence of
parasite in host; to the migration of the parasite; loss to host
by feeding of parasites; injury by certain toxins.
STILES, C. W. Diseases Caused by Animal Parasites. Osler’s
Mod. Med., Vol. I, 1907, p. 525. General discussion; Tre-
matodes; Cestodes; Roundworms; Acariasis; Parasitic Insects;
Myiasis.
Van BENEDEN, P. J. Animal Parasites and Messmates. 1889.
Contains much that is interesting.
Warp, HENRY B. Influence of Parasitism on the Host. Proc.
Amer. Assn. for Advancement oj Science, Vol. 56, 1907. A
comprehensive statement of this subject. List of literature.
PROTOZOA
Catxins, G. N. The Protozoa. Osler’s Mod. Med., Vol. I,
1907, Pp. 353. General notes on the Protozoa; classification;
reproduction; life-cycle of various forms. Regards Protozoa as
subkingdom and the four great divisions as phyla.
Ca.xins, G. N. Protozodlogy. N. Y., 1909. Chapters on
parasitism, pathogenic Protozoa, etc.
Bibliography 077
CLARKE, J. J. Protozoa and Disease. London, 1903, Pt. I.
Discusses the various protozoa that cause disease, and refers
frequently to those that are transferred from host to host by
insects.
CLARKE, J. J. Protozoa and Disease. London, 1908. Part II,
comprising sections on the causation of smallpox, syphilis and
cancer. Notes on parasitic Protozoa, tropical diseases, ticks,
piroplasmosis, etc.
DaniEts, C. W. Persistence of the Tropical Diseases of Man
Due to Protozoa. Jour. Trop. Med. & Hyg., 12, Aug. 2. 1909,
Ppp. 232-234. Same in Lancet, II, 1909, p. 460. Good sum-
mary of present knowledge of the subject.
Mincuin, E. A. Protozoa. In Albutt and Rolleston’s System
of Medicine, II, 1907, pp. 9-122. A comprehensive chapter
on Protozoa. Many parasitic forms are figured and described.
Bibliography.
Mincuin, E. A. The Sporozoa. In Lankester’s Treatise on
Zool., Pt. I, pp. 150-360, 1903. Best account of this group,
list of Sporozoan hosts. Bibliography.
BACTERIA
FLEXNER, SIMON. Relation of Bacteria and Sporozoa to Dis-
ease. Science, N. S., Vol. 27, No. 682, pp. 133-136. On
these pages discusses relation of bacteria and Protozoa to
human diseases.
Jorpan, Epwin O. General Bacteriology. Philad., 1898. A
good general treatment of the subject.
LrEvy, ERNST, AND KLEMPERER, FELIX. Elements of Clinical
Bacteriology for Physicians and Students (transl. by A. A.
Eschner), Philad., 1909. Morphology and biology of bacte-
ria; infection; immunity; specific diseases of bacterial origin,
etc.
Muir, Rosr., AND RITCHIE, JAS. Manual of Bacteriology.
178 Insects and Disease
N. Y., 1903. Contains chapter on the relation of bacteria to
diseases and discussion of several bacterial diseases.
STERNBERG, G. M. A Manual of Bacteriology. N. Y., 1893.
Part III is devoted to pathogenic bacteria.
INSECTS AND DISEASE
Heros, W. B. Medical Entomology, Its Scope and Methods.
Jour. of Eco. Ento., Vol. 2, No. 4, 1909, pp. 265-268.
Howarp, L. O. Insects as Carriers and Spreaders of Disease.
Year Book U. S. Dept. Agric., 1901, pp. 177-192. Good re-
view of the subject.
Howarp, L. O. How Insects Affect Health in Rural Districts.
U. S. Dept. Agric., Farmers’ Bulletin, No. 155, 1902. Dis-
cussion of city and county conditions; protection from typhoid,
malaria and yellow fever.
Howarp, L. O. Economic Loss to the People of U. S. Through
Insects That Cause Disease. Bull. 78, U. S. Dept. Agric.
Bur. of Ent., 1909. A comprehensive discussion and summary
of the subject. Discusses mosquitoes, flies, the Panama Canal,
epidemic diseases and the progress of nations.
Ketocc, V. L. Insects and Disease, Chap. XVIII, in Amert-
can Insects, pp. 615-654, 1905. Discusses Mosquitoes and
malaria; yellow fever and filariasis.
Kinc, H. H. Report on Economic Entomology of Khartoum,
in Third Rept. of Wellcome Research Lab., 1908. Discusses
insects injurious to man: mosquitoes, blood-sucking insects
other than mosquitoes, etc.
Mason, C. F. The Spread of Diseases by Insects, with Sug-
gestions Regarding Prophylaxis. International Clinics, Vol. I,
1904, pp. 1-21. A brief summary of the subject.
McCraE, JoHN. Recent Progress in Tropical Medicine. In-
ternational Clinics, Vol. II, 1904, pp. 22-36. Discusses several
diseases, some of which are transmitted by insects.
SS ee
Bibliography 179
NutTALL, G. H. F. On the Rdle of the Insects Arachnids and
Myriapods as Carriers in the Spread of Bacterial and Parasitic
Diseases of Man and Animals. A critical and historical study.
Johns Hopkins Hospital Reporis, Vol. 8, 1899, pp. I-154.
A review of all the literature up to this date. Important
article.
NutTAtL, G. H. F. Insects as Carriers of Disease. Recent ad-
vances in our knowledge of the part played by blood-sucking
arthropods (exclusive of mosquitoes and ticks) in the trans-
mission of infectious diseases. Bericht uber den XIV. Intern.
Kongress fur Hygiene und Dermogrophic. Berlin, 1907,
pp. 195-206. Discusses protozoan and bacterial diseases.
STiLEs, C. W. Insects as Disseminators of Disease. Virginia
Medical Semi-monthly, Vol. 6, No. 3, May 10, 1901, pp. 53-58.
Good statement of subject with list of recent workers.
Wuerry, W. B. Insects and Infection. Cal. State Jour. of
Med., Nov., 1907. Discusses the réle of insects, ticks, etc.,
in the transmission of infectious diseases.
Symposium on Yellow Fever and Other Insect-borne Diseases.
Science, N. S., Vol. 23, Nos. 584-585, 1906. The Protozoan
Life-cycle, G. N. Calkins. Filariasis and Trypanosome Dis-
eases, H. B. Ward. The Practical Results of Reed’s Findings
on Yellow Fever Transmission, J. H. White. Difficulties of
Recognition and Prevention of Yellow Fever, Q. Kohnke.
_ The Practical Side of Mosquito Extermination, H. C. Weeks.
Without Mosquitoes There Can Be No Yellow Fever, Jas.
Carroll. Estivo-autumnal Fever, Cause, Diagnosis, Treat-
ment and Destruction of Mosquitoes Which Spread the Dis-
ease, H. A. Veazie.
MOSQUITOES—SYSTEMATIC AND GENERAL
BALFouR, ANDREW, AND STAFF. Second Report of the Wellcome
Research Laboratories at the Gordon Memorial College, Khar
180 Insects and Disease
toum, 1906. Includes reports on work on mosquitoes and
other noxious insects.
BoycrE, SIR ROBERT W. Mosquitoes or Man? The Conquest
of the Tropical World. N. Y., 1909. Reviews medical and
sanitary work in the tropics and discusses the relation of insects
to various tropical diseases.
Buscu, AuGcust. Report on a Trip for the Purpose of Studying
the Mosquito Fauna of Panama. Smith. Miscell. Coll., Vol. 5,
Pt. I, 1908, p. 49. Work that is being done in Panama to
control the mosquitoes. Annotated list of species.
FELT, E. P. Mosquitoes or Culicide of New York State. In
N. Y. State Museum Bull. 79, Entomology 22, 1904. Dis-
cusses distribution, migration and life-history of various species
of mosquitoes and mosquito diseases. Bibliography.
Gites, GEo. M. A Handbook of Gnats or Mosquitoes, Giving
the Anatomy and Life-History of the Culicide. London, 1goz.
Whole subject treated very fully.
Gruss, S. B. Vessels as Carriers of Mosquitoes. Pub. Health
and Mar. Hospt. Ser. Bull. 11, Mar. 3, 1903. Believes that
mosquitoes may come aboard when the vessel is lying at anchor
one-half mile from shore, and that under favorable conditions
they may come aboard when the vessel is fifteen miles from
shore.
Howarp, L.O. Mosquitoes. Osler’s Mod. Med., Vol. I, p. 370,
1907. General notes on classification and habits particularly
in relation to diseases.
Howarp, L. O. Notes on Mosquitoes of the United States.
U.S. Dept. Agric., 1900. Div. of Ento. Bull. No. 25, N. S.
Account of the structure; biology; remarks on remedies.
Howarp, L. O. Concerning the Geographic Distribution of
the Yellow Fever Mosquito. Public Health Rept., Pub.
Health and Mar. Hospi. Ser., Nov. 13, 1903. The same re-
vised to Sept. 10, 1905.
Howarp, L.O. Mosquitoes: How They Live; How They Carry
Bibliography 181
Disease; How They Are Classified; How They May Be De-
stroyed. N. Y., r901. One of the best popular books on
mosquitoes.
McCracken, I. Anopheles in California, with a Description
of a New Species. Entomological News, Vol. 15, Jan., 1904.
Records of three species, their breeding-places, habits, etc.
MITCHELL, EvetyN G. Mosquito Life. N. Y., 1907. A good
popular account of the mosquitoes and their relation to disease.
The appendix treats of mosquitoes and their possible relation
to leprosy.
SmiTtH, J. B. Mosquitoes Occurring Within the State of New
Jersey. Report of the New Jersey State Agric. Exper. Station
upon the mosquitoes occurring within the State. Trenton,
N. J., 1904. Habits, development, relation to disease, checks
and remedies; systematic.
SMITH, J.B. ‘The General Economic Importance of Mosquitoes.
Popular Science Monthly, 70, 1907, pp. 325-329. Mosquitoes
affect not only the health and comfort of the people, but
hinder development of agriculture and thus affect land
values.
SmitH, J. B. The New Jersey Salt-marsh and Its Improve-
ment. New Jersey Agricultural Experiment Station Bulletin,
207, 1907. Shows that the increased value of the land drained
in the antimosquito crusade more than pays for the cost of the
drainage.
THEOBALD, F. V. Monograph of Culicide of the World. Four
Vols. and one Vol. of plates. London, 1gor to 1907. Vol. I
contains 96 pages on structure, life-history, habits, etc. Vol. II
contains a bibliography. Vol. III contains a list of species
that carry disease.
THEOBALD, F. V. Mosquitoes or Culicide. In Albutt and Rol-
leston’s System of Medicine, II, 1907, pp. 122-168. Structure,
life-history, habits, distribution and classification of mosqui
toes. Bibliography.
182 Insects and Disease
MOSQUITO ANATOMY
BERKELEY, WM. M. Laboratory Work with Mosquitoes. N. Y.,
1902. Chapters on development, anatomy, dissection, malarial
parasites, filarial disease, yellow fever.
Dimmock, Geo. Anatomy of the Mouth-parts and Suctorial
Apparatus of Culex. Psyche, 3, pp. 231-241, Sept., 188r.
Good.
Iuus, A. D. On the Larval and Pupal Stages of Anopheles
maculipennis. Journal Hygiene, Vol. 7, No. 2, April, 1907.
Morphology.
Imus, A. D. On the Larval and Pupal Stages of Anopheles
maculipennis. Parasitology, Vol. I, No. 2, June, 1908. Con-
tinuation of article in Jour. Hyg., Vol. 7, No. 2. Continues
discussion of morphology.
NUTTALL, Geo. F., CorBETT, Louis, AND STRANGEWAYS-PIG,
T. Studies in Relation to Malaria. Pt. I, The Geographical
Distribution of Anopheles in Relation to the Former Distribu-
tion of Ague in England. Jour. Hyg., Vol. I, No. 1, Jan., 1gor.
NUTTALL, GEO. F., AND SHIPLEY, ARTHUR E. Studies in Rela-
tion to Malaria. Pt. II, Structure and Biology of Anopheles,
Jour Hyg., Vol. I, No. 1, Jan., 1901: The Egg and Larva;
Bibliography. Pt. II, cont., Vol. I, No. 2, April, r901: The
Pupa. Pt. II, cont., Vol. I, No. 4, Oct., r9g01: Adult External
Anatomy. Pt. II, cont., Vol. 2, No. 1, Jan., 1902: Aitiology
of Adult. Pt. II, cont., Vol. III, No. 2, April, 1903: Anatomy
of Adult. |
THompson, Mittett T. Alimentary Canal of the Mosquito.
Proc. Bost. Soc. Nat. Hist., Vol. 32, No. 6, 1905, pp. 145-202.
Good summary of recent investigations.
WEscHE, W. The Mouth-parts of Nemocera and Their Rela-
tion to the Other Families of Diptera. Royal Microscopic Soc.
Jour., 1904, pp. 28-47. Discussion with illustrations of the
mouth-parts of various Diptera.
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MOSQUITOES—LIFE-HISTORY AND HABITS
Ayers, E. A. The Secrets of the Mosquito. A guide to the
extermination of the prolific pest. World’s Work, 1907,
Vol. 14, pp. 8902-8910. Notes on life-history and methods
of control.
Jorpan, E. O., AND HEFFERAN, Mary. Observations on the
Bionomics of Anopheles. Jour. Injec. Diseases, II, 1905, pp. 56-
69. Occurrence, breeding-places, habits, etc.
Moreau, H. A., AND DUPREE, J. W. Development and Hiberna-
tion of Mosquitoes. Bull. 40, N. S., Div. of Ento., pp. 88-92,
1903. Results of observation on five genera of mosquitoes in
the vicinity of Baton Rouge, La.
Ross, E. H. The Influence of Certain Biological Factors on
the Question of the Migration of Mosquitoes. Jour. Trop.
Med. & Hyg., 12, 1909, pp. 256-258, Sept. 1. Only fecun-
dated females feed on blood, and must be fertilized after each
batch of eggs. ‘This determines largely the time and place of
breeding.
SMITH, J. B. Concerning Migration of Mosquitoes. Sczence, 18,
Dec. 11, 1903, pp. 761-764. Observations on the migrations
of mosquitoes, particularly C. sollicitans.
MOSQUITO FIGHTING
Cett1, ANGELO. The Campaign Against Malaria in Italy.
Transl. by J. J. Eyre. Jour. Trop. Med. & Hyg., XI, Apr. 1,
1908, pp. 101-108. Includes a good discussion of the effective-
ness of destroying the mosquitoes in controlling malaria.
Fett, E. P. Mosquito Control. In Report of the N. Y. State —
Entomologist jor 1905, pp. 109-116. Notes on importance and
methods of control of various species.
GOLDBERGER, Jos. Prevention and Destruction of Mosquitoes.
Public Health Reports, Pub. Health and Mar. Hospt. Ser.,
184 Insects and Disease
July 17, 1908. Life-histories and methods of fighting larve,
pupe and adults.
LE Prince, J. A. Mosquito Destruction in the Tropics. Jour.
Amer. Med. Assn., LI, p. 26, Dec. 26, 1908. Occurrence
and habits of Anopheles, methods of destruction. Results of
anti-malarial work on the isthmus. Discussion by various
doctors.
QuayvLe, H. J. Mosquito Control Work in California. Bull.
No. 178, Calif. Agric. Ex. Sta., pp. 1-55, 1906. Habits and
life-history of California species, with an account of experi-
ments to control the salt-marsh species.
ROSENAN, M. J. Disinfection Against Mosquitoes with For-
maldehyde and Sulphur Dioxid. Hyg. Lab. Pub. Health and
Mar. Hospt. Ser., Bull. 6, 1got.
Ross, RoNALD. Mosquito Brigades and How to Organize Them.
New York, 1902.
Ross, RoNALD. Logical Basis of the Sanitary Policy of Mosquito
Reduction. Science, N. S., Vol. 22, No. 750, Dec. 1, 1905,
pp. 689-699. Important article dealing with the methods of
control.
SmitH, J. B. Salt-marsh Mosquitoes. New Jersey Agric.
Exper. Stn. Special Bulletin T, 1902. Breeding-places and
methods of control of this species.
SmitH, J. B. Mosquitocides. Bull. 40, New Series U. S. Dept.
Agric., Div. of Ento., pp. 96-108, 1903. Results of experi-
ments with a number of substances, several of which were
found. to be effective and some cheap enough to permit of
their use to a limited extent.
SmitH, J. B. The New Jersey Salt-marsh and Its Improve-
ment. Bull. No. 207, Nov. 14, 1907, New Jersey Agric.
Exper. Stn. Results of draining the marshes to get rid of
mosquitoes.
SmitH, J. B. The House Mosquito: a City, Town and Village
Problem. N. J. Agric. Ex. Sin. Bull. 216, 1908. Work done
Bibliography 185
on salt-marshes since 1904 practically eliminated the migratory
species, so that C. pipens, the house mosquito, is now the
problem. Life-history and methods of combating.
UnpDERwoop, W. L. Mosquitoes and Suggestions for Their
Extermination. Pop. Sci. Mo., Vol. 63, 1903, pp. 453-466.
Life-history, habits and methods of control.
UnpDERWooD, W. L. The Mosquito Nuisance and How to
Deal with It. Boston, 1903.
First Antimosquito Convention, 1903. Pub., Brooklyn, 1904.
Contains articles on what railroads, government and laws
should do toward mosquito extermination; mosquito work in
Havana; how state appropriations should be used, etc.
National Mosquito Extermination Society. Bulletin No. 1,
1904. Object of Society; brief sketches of Ross, Reed, and
others. Reprints of a few articles on mosquito extermination.
American Mosquito Extermination Society. Year Book for
1904-05. N. Y., 1906. Containing reports of meetings and
discussions of various problems. Several interesting papers,
among them “ Criminal Indictment of the Mosquito,” F. W.
Moss. “ Mosquito Work at Panama Canal,” W. C. Sorgas.
“ Diversities Among New York Mosquitoes,” E. P. Felt.
“Mosquito Extermination in New Jersey,” J. B. Smith.
“ The Mosquito Question,’”? Quitman Kohnke.
Antimalarial Work in the Panama Canal Zone. Editorial in
Jour. Trop. Med. & Hyg., XI, Aug. 15, 1908, p. 251. Notes
on the success of the measures adopted there.
MOSQUITOES AND DISEASE
Doty, A. H. The Mosquito, Its Relation to Disease and Its
Extermination. New York State Journal of Medicine, May,
1908.
FInLAy, Cas. Mosquitoes Considered as Transmitters of
Yellow Fever and Malaria. Med. Record, May 27, 1899,
186 Insects and Disease
Pp. 737-739. Review of his theory in regard to mosquitoes
and disease and the probable necessary changes in view of
recent discoveries.
Howarp, L. O. Mosquitoes as Transmitters of Disease. Re-
view of Reviews, XXIV, 1901, pp. 192-195. A review of the
work of various investigators.
SMITH, J. B. Sanitary Aspect of the Mosquito Question. Medi-
cal News, Mar. 7, 1903. Note on mosquitoes and their rela-
tion to disease.
TAyYLor, J. B. Observations on the Mosquitoes of Havana,
Cuba. Reprint from La Revista de Medicina, June, 1903, p. 27.
MALARIA
Banks, C. S. Experiments in Malarial Transmission by Means
of Myzomyia ludlowtt. Phil. Jour. Sci., B. 2, 1907, pp. 513-
535. Breeding-places of mosquitoes, life-histories of the spe-
cies; mosquitoes and malaria.
Craic, C.F. Malarial Fevers. Osler’s Mod. Med., Vol. I, p. 392,
1907. Historical; distribution; malarial parasites; classification;
development; malarial mosquitoes; pathology; treatment, etc.
Craic, C. F. Studies in the Morphology of Malarial Plasmodia
after the Administration of Quinine and in Intracorpuscular
Conjugation. Jour. Injec. Diseases, VII, No. 2, 1910. See
also same, IV, 1907, pp. 108-140. Gives the evidence upon
which he bases his theory of the meaning of intracorpuscular
conjunction.
Craic, C. F. The Malarial Fevers, Hemoglobinuric Fever and
the Blood Protozoa of Man. N. Y., 1909. A thorough con-
sideration of the subject of malaria and good discussion of
the other subjects noted in title. Bibliography.
DEADERICK, W. H. Malaria. Philad., 1909. The chapter on
etiology treats of the transmission by mosquitoes.
Harris, S. Prevention of Malaria. Jour. Amer. Med. Assn., 53,
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Oct. 9, 1909, pp. 1162-67. Effects of malaria; transmission
by mosquitoes, etc. In the discussion of the paper J. H. White
summarizes the fight against yellow fever in New Orleans.
Herrick, G. W. Relation of Malaria to Agriculture and Other
Industries of the South. Economic losses occasioned by
malaria; malaria responsible for more sickness among the
white population than any other disease; relation to mosqui-
toes. Pop. Sct. Mo., Vol. 62, Apr., 1903, pp. 521-525.
Jones, Ross, ExtetTt. Malaria. London, 1907. Small book,
introduction by Ross. Malaria in Greece and Italy; shows
how this disease contributed to the downfall of great nations.
MANNABERG, JuLIuS. Malaria. In Nothnagel’s Encyclopedia
of Practical Med., Amer. Ed., 1905, pp. 17-494. A very com-
prehensive discussion of the disease and the relation of mos-
quitoes to the malarial parasite.
Manson, Patrick. The Mosquito and the Malaria Parasite.
Brit. Med. Jour., Vol. II for 1898, pp. 849-853. History of
the parasite in the human and insect host; observations of
Ross and others and their meaning.
Manson, Patrick. Experimental Demonstration of the Mos-
quito-malarial Theory. Brit. Med. Jour., Vol. 2 for 1900,
Pp. 949-951, also Lancet, II, 1900, pp. 923-925. Infected
mosquitoes sent from Rome allowed to bite men in England
who had not been in malarial regions. Malarial fever
followed.
Manson, Patrick. Malarial Fever. Appendix to Vol. IX of
T. C. Albutt’s System of Med., 1900. Relation of the malarial
parasite to the disease and to mosquitoes.
ROBERTSON, E. W. Renaming of Malaria—Anophelesis. Va.
Medical Semi-monthly, Sept. 10, 1909. Considers malaria a
misnomer and gives reasons for suggesting new name.
Ross, RONALD. On Some Peculiar Pigmented Cells Found in
Two Mosquitoes Fed on Malarial Blood. Brit. Med. Jour.,
1897, Dec. 18, p. 1786. Records in his experiments in feeding
188 Insects and Disease
mosquitoes on blood of malarial patients. Records finding the
parasites in some of them. Important article.
Ross, RONALD. Pigmented Cells in Mosquitoes. Brit. Med.
Jour., 1898, Feb. 26, p. 550. Further notes on them.
Ross, RonaLtD. The Mosquito Theory of Malaria. Report
dated Calcutta, Feb. 16, 1899. Reprinted in Pop. Sci. Monthly,
Vol. 56, Nov., 1899, pp. 42-46. ‘Tells of his investigations in
India and their results.
Ross, RONALD. The Relationship of Malaria and the Mosquito.
Lancet, II, 1900, July 7, p. 4880. Observation on the trans-
mission of malaria.
Ross, Ronatp. Malaria Fever, Its Cause, Prevention and
Treatment. London, 1902. Chapters on malaria, mosquitoes,
prevention and treatment.
Ross, RoNALD. Parasites of Mosquitoes. Jour. of Hyg., VI,
No. 2, Apr., 1906. Brief review of several of his earlier papers
on this subject with additional notes.
Stupson, W. J. R. Recent Discoveries Which Have Rendered
Antimalarial Sanitation More Precise and Less Costly. Brit.
Med. Jour., 1907, II, pp. 1044-46. Discussion of the various
factors in mosquito control.
STEPHENS, J. W. W., AND CHRISTOPHERS, S. R. The Practical
Study of Malaria and Other Blood Parasites. London, 1908.
Chapters on mosquitoes, flies and ticks and their relation to
diseases.
STERNBERG, G. M. The Malarial Parasite and Other Patho-
genic Protozoa. Pop. Sct. Mo., Vol. 50, 1897, pp. 628-641.
Account of the discovery of the malarial parasite and more
recent studies on it.
STERNBERG, G. M. Malaria. Smith. Rept., 1900, pp. 645-656.
Review of the experimental evidence in support of the mosquito-
malaria theory.
Malarial Fever. Jour. Trop. Med. & Hyg., II, Mar. 16, 1908,
pp. 96-98. A list of literature mostly for the years 1906 and 1907.
Bibliography | 189
YELLOW FEVER
Apvams, S. H. Yellow Fever, a Problem Solved. The battle of
New Orleans against the mosquito. McClure’s Magazine,
Vol. 27, June, 1906, p. 178. An interesting popular article.
CARROLL, JAMES. Yellow Fever. Osler’s Mod. Med., Vol. II,
1907, p. 736. History, etiology, treatment. A good review of
the work of the Yellow Fever Com. and the results of their work.
CARROLL, JAMES. The Transmission of Yellow Fever. Amer.
Med. Assn., 40, 1905, pp. 1429-33. Shows the relation of the
mosquito to the disease.
CARROLL, JAMES. Yellow Fever. Lessons to be learned from
the present outbreak of yellow fever. Jour. of Amer. Med.
Assn., Vol. 45, 1905, pp. 1079-81. Among other things rec-
ommends that mosquitoes be kept from patients.
CHAILLE, S. E. The Stegomyia and Fomites. Amer. Med.
Assn., 40, 1903, pp. 1433-40. Concludes that the mosquito is
the only proven disseminator of yellow fever. Extended dis-
cussion by various physicians.
DastrE, A. The Fight Against Yellow Fever. Smith. Rept.,
1905, pp. 339-350. History of the yellow fever epidemics, its
geographical distribution, and the work that is being done to
control it.
Doty, A. H. On the Mode of Transmission of the Infectious
Agent in Yellow Fever and Its Bearing upon the Quarantine
Regulations. Med. Record, Oct. 26, 1901, pp. 649-653. Re-
view of older theories in regard to the spread of yellow fever.
Believes that the quarantines are now unnecessary.
FINLEY, CHAS. The Mosquito Theory of the Transmission of
Yellow Fever and Its New Development. Med. Record,
Jan. 19, 1901. Refers to his early observations on the subject,
giving extracts from some of his earlier papers to show that
he had long held the mosquito responsible for the dissemina-
tion of yellow fever.
190 Insects and Disease
GOLDBERGER, Jos. Yellow Fever, A‘tiology, Symptoms and
Diagnosis. Yellow Fever Inst. Bull. 16, Pub. Health and
Mar. Hospt. Ser., 1907. Includes discussion of the relation
of mosquitoes to the disease.
GUITERAS, JOHN. Experimental Yellow Fever at the Inocula-
tion Station of the Sanitary Department of Havana. Amer.
Med., Vol. II, No. 21, 1901, pp. 809-817. Experiments show
that all types of the yellow fever from mild to severe may be
produced by the bite of the mosquito.
McFARLAND, JOSEPH. Life and Work of James Carroll. Mem-
oir read at the fifth annual meeting of the Soc. of Tropical
Med., 1908. Early life of Carroll and his work with the Yellow
Fever Com.
PARKER, H. B., BEvER, G. E., AND PotHiER, O. L. Rept. of
Working Party No. 1, Yellow Fever Institute. Bull. 13, Pub.
Health and Mar. Hospt. Ser., 1903. As a result of their studies
they believe that the disease is caused by a protozoan parasite
which they name and describe. Discuss the relation of mos-
quitoes to the disease.
REED, WALTER; CARROLL, JAMES; AND AGRAMONTE, A. Experi-
mental Yellow Fever. Amer. Med., July 6, 1901, pp. 15-23.
Records of certain experiments and their results.
REED, WALTER; CARROLL, JAMES; AND AGRAMONTE, C. A. The
Etiology of Yellow Fever. A preliminary note presented at the
Amer. Pub. Health Assn. Philad. Med. Jour., Oct. 27, 1900, pp.
790-796. Also an additional note in Jour. Amer. Med. Assn., 36,
Pp. 431-440, 1901. Records of their experiments and a sum-
ming up of the data in regard to yellow fever and the mosquito.
REED, WALTER, AND CARROLL, JAMES. ‘The Prevention of
Yellow Fever. Med. Record, Oct. 26, 1901, pp. 441-449.
History of the disease, especially in U. S., results of the work
of Yellow Fever Com. description, life-history and habits of
the mosquito, its relation to yellow fever, methods of control.
Important paper.
Bibliography 1g!
REED, WALTER. Recent Researches Concerning the Attiology,
Propagation and Prevention of Yellow Fever by U. S. Army
Com. Jour. Hyg., 2, 1902, pp. 101-119. Review of work
of the Yellow Fever Com. and the importance of the results.
Bibliography.
ROSENAN, M. J., PARKER, H. B., FRANCIS, E., AND BEYER, G. E.
Rept. of Working Party No. 2, Yellow Fever Institute. Ex-
perimental studies in yellow fever and malaria at Vera Cruz,
Mex. U.S. Pub. Healih and Mar. Hospt. Ser., May, 1904.
Includes experiments and observations on mosquitoes.
ROoSENAN, M. J., AND GOLDBERGER, Jos. Report of Working
Party No. 3, Yellow Fever Institute. Yellow Fever Inst.
Bull. 15, Pub. Health and Mar. Hospt. Ser., 1906. Unsuc-
cessful attempts to grow the yellow fever parasite. Negative
results in the experimental study of the hereditary transmis-
sion of the yellow fever in the mosquito. Appendix A gives a
translation of Marchoux and Simonds’ report in which they
report positive results in their experiments alone the same line.
STERNBERG, G. M. Transmission of Yellow Fever by Mos-
quitoes. Smith. Rept., 1900, pp. 657-673. Review of the early
theories in regard to yellow fever and the work and findings of
the yellow fever commission.
WaitE, J. H. Yellow Fever and the Mosquito. Jour. Amer.
Med. Assn., LI, No. 26, Dec. 26, 1908. Considers both S.
calopus and C. pungens. Results of early mistakes. Neces-
sity of destroying mosquito. Methods of destroying mosquito.
Habits of mosquito.
Abstract of the Report of the French Yellow Fever Com. at
Rio de Janeiro, 1903. Pub. Health Report, Pub. Health and
Mar. Host. Ser., Vol. 19, Pt. I, p. ror9. A summary of their
findings and conclusions to the date of report. |
DE YBARRA, A. M. F. Yellow Fever Again in Cuba. Jour.
Trop. Med. & Hyg., XI, Mar. 2, 1908, pp. 73-78. Cites a
number of cases of yellow fever within the last few years and
192 Insects and Disease
uses them as evidence to show that the disease may be trans-
mitted in other ways than by the mosquito. A strong summing
up of the arguments against the mosquito theory. Reprint of
editorial in Tex. Med. Jour., Oct., 1907, also follows this
article.
The Extinction of Yellow Fever at Rio de Janeiro. Lancet, II,
1909, p. 404. A review of a French publication giving the re-
sults of the work from 1903 to present time. In 1903 before
work was begun there were 584 deaths from yellow fever. In
1908 only 4, and none so far in 1909. Success accredited to
mosquito work and general sanitation.
A Pioneer in Research on Yellow Fever. Editorial in Brit. Med.
Jour., May 30, 1908, p. 1306. Refers to the work of L. D.
Beauperthuy, who, in 1853, set forth the theory that yellow
fever was transmitted by mosquitoes.
DENGUE
ASHBURN, P. M., AND Craic, C. F. Experimental Investiga-
tions Regarding the AZtiology of Dengue Fever. Jour. Injec.
Diseases, Vol. V, 1907, pp. 440-475. Conclude that the
disease is spread only by mosquitoes.
CoLtEMAN, THomas D. Dengue. Osler’s Mod. Med., Vol. II,
1907, p. 489. Etiology, pathology, etc.; possibility of Culex
jatigans disseminating the disease.
GraHaAM, H. “The Dengue”; a Study of Its Pathology and
Mode of Propagation. Jour. of Trop. Med. & Hyg., July 1,
1903, p. 209. Experiments which seem to show that dengue
is transmitted by Culex fatigans.
LEICHTENSTERN, O. Dengue. In Nothnagel’s Encyclopedia of
Practical Med., Amer. Ed., 1905, pp. 720-743. Consideration
of the disease and its transmission.
Ross, E. H. The Prevention of Dengue Fever. Amer. Trop.
Med. & Parasii., Vol. II, No. 3, July 1, 1908, pp. 193-195.
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A successful campaign against the mosquitoes in Port Said in
1906 stopped the outbreaks of malaria and dengue.
Dengue and Sand-flies. Jour. Trop. Med. & Hyg., 12, 1909,
pp. 172-173. A note on these pages refers to the work of Dr.
R. Doerr, who suspects that dengue may be carried by sand-
flies, Phlobotomus, as well as by mosquitoes.
FILARIAL DISEASES AND ELEPHANTIASIS
CHRISTOPHERS, S. R. What Is Really Known of the Cause of
Elephantiasis. Ind. Med. Gaz., Nov., 1907, p. 404. Ques-
tions Manson’s theory in regard to the disease being caused by
filaria.
Manson, Patrick. Tropical Diseases. London, 1908, pp. 594-
648. A most comprehensive chapter on filariasis and ele-
phantiasis.
PHALEN, J. M., AND NicHo1s, H. J. Filariasis and Elephantiasis
in Southern Luzon. Phil. Jour. Sct., Sept., 1908. Culex
microannulatus regarded as the carrier of the filaria.
Prout, W. T. On the Réle of Filaria in the Production of
Disease. Jour. Trop. Med. & Hyg., Apr. 1, 1908, p. 109.
Discussion of same in same journal, June 1, 1908.
Waite, Duncan. Filarial Periodicity and Its Association with
Eosinophilia. Jour. Trop. Med. & Hyg., 12, July 15, 1909,
pp. 175-183. Among other things he discusses the relation of
mosquitoes to filarial diseases.
LEPROSY
BRINCKERHOFF, W. R. A Note upon the Possibility of the
Mosquito Acting in the Transmission of Leprosy. Pub.
Health and Mar. Hospt. Ser. (general publications), 1908.
Suggests the possibilities of such transmission, but concludes
that the probabilities are against it.
194 Insects and Disease
GoopHvE, E.S. The Bacillus Lepre in the Gnat and Bedbug.
Ind. Med. Gaz., Vol. XLI, Aug., 1906, p. 342. Has found this
bacillus in mosquitoes and bedbugs, but believes the latter is
more concerned in transmitting the disease.
GoopHvE, E.S. Mosquitoes and Their Relation to Leprosy in
Hawaii. Amer. Med., N. S., 2, 1907, p. 593. Suggests that
mosquitoes may carry the disease, also warns against danger
from flies and bedbugs.
HUvTcHINSON, J. Mosquitoes and Leprosy. Brit. Med. Jour.,
Dec. 22, 1906, Vol. II, p. 1841. Evidence against the insect
theory of transmission of leprosy.
Mucuiston, T. C. Ona Possible Mode of Communication of
Leprosy. Jour. Trop. Med., Vol. VIII, July 15, 1905, p. 209.
Suggests that the itch-mite may be the carrier of leprosy.
Studies on 77 lepers led him to this conclusion.
SmMyTH, W.R. Leprosy. Brit. Med. Jour., Dec. 8, 1906, Vol. II,
p- 1670. Believes that bedbugs or some similar wingless
parasite conveys the disease.
PLAGUE
BRANNERMAN, W. B. Spread of Plague in India. Jour. of Hyg.,
Vol. 6, No. 2, Apr., 1906, pp. 179-211. A digest of experi-
ments made in India. Discusses various ways in which the
disease may be spread. Review of the evidence that insects
may be concerned. Bibliography. .
CALVERT, W. J. Plague. Osler’s Mod. Med., Vol. II, 1907,
p. 760. History; bacteriology; pathology; plague among ani-
mals; transmission, etc.
Ham, B. BuRNETT. Report on Plague in Queensland, ee
P. 153 discusses the rat-flea theory of dissemination of bubonic
plague, summing up the evidence of various observers, includ-
ing the Indian Advisory Com. and others. Considers the evi-
dence conclusive that P. cheopis and possibly C. fasciatus
Bibliography 195
transmit plague. Other pages discuss various rat fleas and
their relation to plague in rats.
Hankin, E. H. On the Epidemiology of Plague. Jour. Hyg., 5,
1905, pp. 48-83. A comprehensive discussion of the disease
and its spread, several pages devoted to rats and fleas; evi-
dence for and against the theory that rats and fleas are the
principal carriers of the disease.
Herzoc, Max. The Plague, Bacteriology, Morbid Anatomy &
Histopathology, Including the Consideration of Insects as
Plague Carriers. Biological Laboratory Bureau of Govt.
Laboratories, Manila, Oct., 1904. Reviews the evidence
regarding the possibility of fleas carrying plague; describes a
new rat flea (Pulex philippinensis); records experiments with
fleas and cites a case of bubonic plague in a child in which the
infection was possibly carried by Pedicult.
McCoy, G. W. Plague Bacilli in Ectoparasites of Squirrels.
Pub. Health Reporis, Pub. Health and Mar. Host. Ser.,
Vol. XXIV, No. 16, Apr. 16, 1909. Experiments with fleas
and lice from infected squirrels demonstrating presence of
plague bacilli.
McCoy, G. W. The Susceptibility of Gophers, Field-mice and
Ground-squirrels to Plague Infection. Jour. of Infec. Diseases,
Vol. 6, 1909, No. 3, pp. 283-288. Gophers highly resistant,
field-mice moderately susceptible and ground-squirrels very
susceptible to plague.
Mitzmain, M. B. Insect Transmission of Bubonic Plague: a
Study of the San Francisco Epidemic. nto. News, 10,
No. 8, 1908, pp. 353-359. Fleas obtained in examination of
1,800 rats. Attempt to locate source of rat and flea introduc-
tion.
Morton, F. M. Eradicating Plague from San Francisco. Re-
port of the Citizens’ Health Com. and an account of its work.
San Francisco, 1909. Discusses the epidemics, methods of
transmission, methods of fighting, etc.
196 Insects and Disease
RucKER, W. C. Plague Among Ground-squirrels in Contra
Costa Co., Cal. Pub. Health Reports, Pub. Health and Mar.
Hospt. Ser., Aug. 27, 1909. Reports of human cases supposed
to be connected with plague among ground-squirrels. Plague
among squirrels; habits, methods of fighting, etc.
RucKER, W. C. Fighting an Unseen Foe. Sunset Mag., XXII,
No. 2, Feb., 1909. Story of the fight against plague in San
Francisco.
SHIPLEY, A. E. Rats and Their Animal Parasites. Jour. Eco.
Biology, Vol. Ill, No. 3, Oct. 28, 1908. List of species of ecto-
and endoparasites.
StmPson, W. J. A Treatise on Plague. Cambridge Univ. Press,
London, 1906. Deals with historical, epidemiological, clinical,
therapeutic and preventive aspect of the disease.
TuHompson, J. A. The Mode of Spread and Prevention of
Plague in Australia. Lancet, Oct. 19, 1907, p. 1104. Rat
fleas the essential factor in transmitting plague, and preventive
methods should be directed against the rats.
THompson, J. A. On the Epidemiology of Plague. Jour. Hyg.,
Vol. VI, No. 5, Oct., 1906. Methods of infection, spread,
relation of rats to the disease and a review of the rat-flea
theory. Bibliography.
VERJBITSKI, D. T. The Part Played by Insects in the Epi-
demiology of Plague. Jour. Hyg., 8, 1908, No. 2, pp.
162-208. Record of extensive experiments with fleas. Fleas
communicated plague for three days, bedbugs for five days.
Interrelation of fleas, rats, dogs, cats, and man. An important
article translated from Russian.
WHeERRY, W. B. Further Notes on the Rat Leprosy and on the
Fate of the Human and Rat Leper Bacillus in Flies. Jour.
Injfec. Diseases, Vol. 5, No. 5, 1908. Discussion and references,
experiments with flies, summary, etc. More than 1,115 lepra-
like bacilli were counted in a single fly-speck.
WHerry, W. B. Plague Among the Ground-squirrels of Cali-
Bibliography 197
fornia. Jour. Injfec. Diseases, Vol. 5, No. 5, 1908, pp. 485-533.
How the plague was first discovered among rats, records of
cases and a discussion of the possible relation of this to human
plague cases. |
Eradicating Plague in San Francisco; Report of the Citizens’
Health Committee, 1909. An account of the recent outbreaks
and the methods of fighting them.
Report of the Indian Plague Commission, Vol. V, pp. 75-77,
igor. In these pages the Commission considers the question
of the transference of plague by suctorial insects. It con-
siders Simonds’ claims and others and believes that ‘‘suctorial
insects do not come under consideration with the spread of
plague.”
Reports on Plague Investigations in India Issued by the Ad-
visory Committee Appointed by the Sec. of State for India,
the Royal Society and the Lister Institute. The reports in-
clude the reports of the Working Commission appointed by
the Advisory Committee and reports on various contributory
investigations. They are published in the Jour. of Hygiene
as “Extra Plague Numbers.” All these reports deal very
largely with the relation of the rat and flea to plague, and are
commonly referred to as “‘Reports of Indian Plague Commis-
sion.” ‘The first number, Vol. VI, Sept., 1906, contains
articles on “Experiments upon the Transmission of Plague
by Fleas.”” ‘Note on the Species of Fleas Found on Rats,
Mus rattus and Mus decumanus in Different Parts of the
World.” ‘The Physiological Anatomy of the Mouth-parts
and Alimentary Canal of the Indian Rat Flea, Pulex cheopis,”
and other papers on the relation of rats to plague. The second
number, Vol. VII, July, 1907, contains articles on ‘‘On the
Significance of the Locality of the Primary Bubo in Animals
Infected with Plague in Nature,” “Further Observations on
the Transmission of Plague by Fleas with Special Reference
to the Fate of Plague Bacillus in the Body of the Rat Flea,”
198 Insects and Disease
“Experimental Production of Plague Epidemics Among Ani-
mals,” ‘‘Experiments in Plague Houses in Bombay,” “On
the External Anatomy of the Indian Rat Flea and Its Differ-
entiation from Some Other Common Fleas,” ‘‘A Note on
Man as a Host of the Indian Rat Flea,” and others on the
relation of rats to plague. The third number, Vol. VII,
Dec., 1907, contains articles on ‘‘Digest of Recent Observa-
tions on the Epidemiology of Plague” (Bibliography), “‘Epi-
demiological Observations in Bombay City,” “‘ Epidemiological
Observations in the Villages of Wadhala, Parel, Worli in
the Neighborhood of Bombay Village,’’ ‘‘General Considera-
tions Regarding the Spread of Infection, Infectivity of Houses,
etc., in Bombay City and Island,” ‘‘ Epidemiological Observa-
tions in the villages of Dhand and Kasel (Punjab).” The
fourth number, Vol. VIII, May, 1908, contains articles on ‘‘’‘The
Part Played by Insects in the Epidemiology of Plague” (see
also ref. under D. T. Verjbitski), ‘‘Observations on the Bio-
nomics of Fleas with Special Reference to P. cheopis,” “The
Mechanism by Means of Which the Flea Cleans Itself of
Plague Bacilli,” ‘‘On the Seasonal Prevalence of Plague in
India.”
See also under Fleas.
FLEAS
Baker, C. F. Fleas and Disease. Science, N. S., Vol. 22,
No. 559, Sept..15, 1905, p. 340. Discusses the possibility of
fleas transmitting leprosy. !
Doane, R. W. Notes on Fleas, Collected on Rat and Human
Hosts in San Francisco and Elsewhere. Can. Ento., 40, 1908,
Pp. 303-304. Shows that Ceraiophyllus fasciatus and Pulex
irritans are common on both man and rats.
Fox, Carrot. The Flea in Its Relation to Plague, with a
Synopsis of the Rat Fleas. The Military Surgeon, 24, June,
1909, pp. 528-537. Review of the work of the Indian
Bibliography 199
Plague Commission and others. Key for identification of rat
fleas.
GALLI-VALERIO. The Part Played by Fleas of Rats and Mice
in the Transmission of Bubonic Plague. Jour. Trop. Med.,
Feb., 1902. Attacks the theory that plague can be conveyed
from rats to men by fleas because rat fleas do not bite men.
McCoy, G. W. Siphonapiera Observed in the Plague Cam-
paign in California with a Note upon Host Transference.
Pub. Health Report, Pub. Health and Mar. Hospt. Ser.,
Vol. XXIV, No. 29, July 16, 1909. Lists of species from
various hosts. Report on experiments in transferring rat
fleas to squirrels and squirrel fleas to rats.
McCoy, G. W., AND Mirzmain, M. B. An Experimental In-
vestigation of the Biting of Man by Fleas Taken from Rats
and Squirrels. Public Health Report, XXIV, No. 8, Feb. 19,
1909, pp. 189-194, Rat and squirrel fleas will bite man.
Mitzmain, M. B. Insect Transmission of Bubonic Plague. A
Study of the San Francisco Epidemic. Entomological News,
Oct., 1908. Source and distribution of species of fleas and
brief notes on work of Indian Plague Commission.
Mirzmain, M. B. How a Hungry Flea Feeds. Entomological
News, Dec., 1908.
Mitzmain, M. B. Some New Facts on the Bionomics of the
California Rodent Fleas. Annals Ento. Soc. Amer., III, pp. 61-
82, IQIo.
SHIPLEY, A. E. Rats and Their Animal Parasites. Jour. oj
Economic Biology, Vol. 3, No. 3, Oct. 28, 1908. List of species
ecto- and endoparasites.
See also reports of Advisory Commission under Plague.
TYPHOID FEVER
ANDERSON, J. F. The Differentiation of Outbreaks of Typhoid
Fever Due to Water, Milk, Flies and Contact. Amer. Jour.
Pub. Health, 19, pp. 251-259. Discusses flies and typhoid.
2.00 Insects and Disease
McCrea, THomAs. ‘Typhoid Fever. Osler’s Mod. Med.,
Vol. II, p. 70, 1907. A full discussion of this disease.
REED, WALTER; VAUGHAN, V. C., AND SHAKESPEARE, E. O.
Abstract of Report on the Origin and Spread of Typhoid
Fever in the U. S. Military Camps During the Spanish War
of 1898. Washington, Govt. Printing Office, 1900. Shows
among other things that ‘‘flies undoubtedly served as carriers
of infection.”
RosEMAN, M. J., LumMspEn, L. L., AND KAsTLE, J. H. Report
on Origin and Prevalence of Typhoid Fever in D.C. Including
reports by Stiles, Goldberger and Stimson. Bull. 35 of Hygzenic
Laboratory of U.S. Public Health and Mar. Hospt. Ser., 1907.
(Second report in Bull. 44, 1907, includes nothing about insects.)
VEEDER, M. A. Typhoid Fever from Sources Other Than
Water Supply. Med. Record, 62, pp. 121-124, July 26, 1902.
Cites several instances where flies might act as the carriers of
the disease.
WHIPPLE, GEO. C. Typhoid Fever, Its Causation, Transmission
and Prevention. N. Y., 1908. Considers that house-flies and
probably fruit-flies carry typhoid bacilli.
HOUSE-FLIES; ANATOMY, LIFE-HISTORY, HABITS
FELT, E. P. Observations on the House-fly. Jour. Eco. Ento.,
III, No. 1, Feb., 1910, pp. 24-26. Shows that it does not breed
freely in darkness.
GriFFiTH, A. The Life-history of House-flies. Public Health
(London), 21, No. 3, 1908, pp. 122-127. Study of life-history.
Flies require water frequently, eggs hatch in twenty-four hours,
larval stage four days. Each female may lay four batches of
eggs. Destroy manure and rubbish.
Hamer, W.H. The Breeding of Flies Summarized. Am. Med.,
3, 1908, p. 431. Habits of flies and experiments to show that
they may carry the germs of various diseases.
Bibliography 201
HEPworTH, JOHN. On the Structure of the Foot of the Fly.
Quar. Jour. Micro. Sci., TI, 1859, pp. 158-563. One plate
showing feet of different flies. A review of the older theories
of how a fly was able to walk on smooth surfaces.
Heros, W. B. The Essentials of House-fly Control. Bull. of
Berkeley Board of Health, Berkeley, Cal., 1909. Recommends
removing manure as soon as possible and keeping it in tight
bins until removed. No very satisfactory insecticides have
been found for use in treating manure piles.
Heros, W. B. The Berkeley House-fly Campaign. Cal. Jour.
of Technology, Vol. XIV, No. 2, 1909. Discusses the methods
that have been used in fighting the fly in Berkeley, Cal. Re-
moving manure regularly or keeping it in closed bins recom-
mended.
Hewitt, C. G. A Preliminary Account of the Life-history of
the Common House-fly. Mem. and Proc. Manchester Lit.
Phil. Soc., 1906, Vol. 51, pp. 1-4.
Hewitt, C.G. On the Bionomics of Certain Calyptrate Mucide
and Their Economic Significance with Especial Reference to
Flies Inhabiting Houses. Jour. Econ. Biol., 1907, Vol. II,
pp. 79-88. Character and importance of group and notes on
many species.
HeEwi1T, C. G. Structure, Development and Bionomics of the
House-fly, Muca domestica. Part I, Quar. Jour. Micro. Sci.,
1907, Pp. 395, On anatomy, external and internal, and bibli-
ography. Part II, same; 1908, p. 495. Breeding-habits,
development and anatomy of larve, bibliography. Part III,
same; 1909, pp. 347-414. ‘The bionomics, allies, parasites,
and the relations to human disease. The best article on the
house-fly.
Howarp, L. O. Further Notes on the House-fly. Bull. 10,
U. S. Dept., Agric. Div. of Ento., p. 63, 1898. Experiments
to kill larve in manure.
Howarp, L. O. House-flies. U.S. Dept. of Agric., Bureau of
202 Insects and Disease
Ento., Circular No. 71, revised ed., 1906. Methods of control
of house-fly and related species.
Howarp, L. O., AnD Martattr, C. L. Bull. 4, U. S. Dept.
Agric., Div. of Ento., pp. 43-47, 1896. General account with
methods of controlling.
Jerson, F. P. The Breeding of the Common House-fly During
the Winter Months. Jour. Econ. Biol., 4, 1909, pp. 78-82.
Records of certain experiments which show that the flies will
breed in winter under favorable conditions.
NEWSTEAD, R. Preliminary Report on the Habits, Life-cycle
and Breeding-places of the Common House-fly as Observed
in the City of Liverpool, with Suggestions as to the Best Means
of Checking Its Increase. Liverpool, Oct. 3, 1907.
NEWSTEAD, R. On the Habits, Life-cycle and Breeding-places
of the Common House-fly. Ann. Trop. Med. Para., Vol. I,
No. 4, Feb. 29, 1908, pp. 507-520. Final report on this sub-
ject. Sums up notes on life-history, habits, breeding-places,
etc. Important article.
PackarD, A. S. On the Transformation of the Common House-
fly with Notes on Allied Forms. Proc. Boston Soc. Nat. Hist.,
Vol. XVI, 1874, pp. 136-140. Life-history and anatomy.
Witcox, E. V. Fighting the House-fly. Country Life in Amer-
ica, May, 1908. Methods of controlling this pest.
HOUSE-FLIES AND TYPHOID
AusTEN, E. E. The House-fly and Certain Allied Species as
Disseminators of Enteric Fever Among the Troops in the
Field. Jour. Roy. Army Med. Corps, June, 1904. Suggests
that it may carry enteric fever and other diseases; method of
control.
Fett, E. P. The Typhoid or House-fly and Disease. In 24th
Rept. of State Ento. in N. Y. State Museum Bull., No. 455,
1909. A general discussion with complete bibliography.
Bibliography 203
FirtH, R. H., anpD Horrocks, W. H. An Inquiry Into the In-
fluence of Soil, Fabrics, and Flies in the Dissemination of
Enteric Infection. Brit. Med. Jour., Vol. II, 1902, pp. 936-
942. House-flies carry enteric bacilli. They may pass through
digestive tract and remain virulent.
Hamitton, AticE. The Fly as a Carrier of Typhoid. Jour.
Amer. Med. Assn., 40, 1903, pp. 576-83. A study of a typhoid
outbreak in Chicago gives good evidence that the flies were
important factors in the spread of the disease.
Hewi1t, C. G. The Biology of House-flies in Relation to
Public Health. Royal Inst. Pub. Health Jour., Oct., 1908.
Howarp, L. O. A contribution to the Study of the Insect
Fauna of Human Excrement. Proc. Wash. Acad. Sct., 2,
1900, pp. 541-600. Special reference to the house-fly and
typhoid fever.
Howarp, L. O. Flies and Typhoid. Pop. Sct.. Mo., Jan.,
1901, pp. 249-256. A popular account of several species of
flies that may be concerned in carrying typhoid.
Krein, E. Flies as Carriers of B. typhus. Brit. Med. Jour.,
Oct. 17, 1908, pp. 1150-51. In cultures made from flies he
found great numbers of B. colt communis and B. typhosus,
showing that flies may carry these germs.
Martin, A. Flies in Relation to Typhoid and Summer Diarrhea.
Public Health, 15, 1903, pp. 652-653. Believes that the
house-fly is largely responsible for these diseases.
REED, WALTER. War Dept. An. Rept., 1899, pp. 627-633.
Flies the cause of a typhoid outbreak in army in 1899.
HOUSE-FLY AND VARIOUS DISEASES
BucHANAN, R. A., Grasc, F. F., AnD M. B. The Carriage
of Infection by Flies. Lancet, 173, 1907, pp. 216-218. Flies
carry various germs on their feet and distribute them where
they walk. Must protect food from contamination.
204 Insects and Disease
BREWSTER, E. T. The Fly. The Disease of the House. Me-
Clures Magazine, XXXIII, No. 5, Sept., 1909, pp. 564-568.
Proposes to make use of tropisims for ridding the houses of
flies.
CASTELLANI, ALDO. Experimental Investigation on Frambesia
tropica (Yaws). Jour. of Hyg., Vol. VII, 1907, pp. 558-599.
On pages 566-568 he discusses the part played by insects in
transmitting the disease. Gives detail of experiments con-
ducted and concludes that under certain conditions yaws may
be conveyed by flies and possibly other insects.
Coss, J. O. Is the Common House-fly a Factor in the Spread
of Tuberculosis? Amer. Med., 9, 1905, pp. 475-477. Be-
lieves that the bacilli may enter the system through the di-
gestive tract and that flies carry them to our food.
Dickenson, G. K. The House-fly and Its Connection with
Disease Dissemination. Med. Record, 71, 1907, pp. 134-139.
Summary; bibliography.
EsTENn, W. M., AND Mason, C. J. Sources of Bacteria in Milk.
Storr’s Agric. Ex. Sin., Conn. Bull., 51, 1908. Shows how
flies may carry bacteria to milk. ‘Table showing number of
bacteria on flies from various sources.
FELT, E. P. The Economic Status of the House-fly. Jour. Eco.
Ento., Vol. 2, No. 1, Feb., 1909, pp. 39-45. A summary of
the charges, possibilities, proofs, etc. Discussion.
GuDGER, E. W. Early Note on Flies as Transmitters of Disease.
Science, N.S. Vol. 31, Jan. 7, 1910, pp. 31-32.
Hamer, W. H. Nuisance from Flies. London County Council
Rept. No. 1,138, pp. 1-10, and No. 1,207, pp. 1-6, 1908.
Observations on various flies and their relation to dis-
eases.
Haywarp, E. H. The Fly as a Carrier of Tuberculosis Infec-
tion. N. Y. Med. Jour., 80, 1904, pp. 643-644. ‘Tubercular
bacilli pass through the digestive tract of flies and remain
virulent.
Bibliography 205
Howarp, L. O. The Carriage of Disease by Flies. Bull. 30,
N. S., pp. 39-45, U. S. Dept. Agric., Div. of Ento., 1901.
Discussion of flies as carriers of disease.
Howarp, L. O. House-flies. U.S. Dept. of Agric., Bureau of
Ento., Cir. No. 71, revised ed., Sept. 21, 1906. Notes on the
various species visiting houses; habits; methods of control;
regulations for controlling flies in cities.
Hutcuinson, Woops. The Story of the Fly That Does Not
Wipe Its Feet. Sat. Evening Post, March 7, 1908.
Jackson, DanieEL D. Conveyance of Disease by Flies Sum-
marized. Bost. Med. & Surg. Jour., 1908, p. 451. Disease
and flies prevail at same time; records over 1,000,000 bacteria
to each fly caught on swill-barrels.
Jackson, Daniet B. Pollution of New York Harbor as a
Menace to Health by the Dissemination of Intestinal Diseases
Through the Agency of the Common House-fly. Account of
experiments and deductions. Pamphlet issued July, 1908, by
Merchants’ Assn. of New York.
LEIpy, JosEPH. Flies as a Means of Communicating Contagious
Diseases. Proc. Acad. Nat. Sci. Phil., 23, 1871, p. 297. Be-
lieves that flies may carry disease; refers to flies in connection
with gangrene and wounds.
Lorp, F. T. Flies and Tuberculosis. Bost. Med. & Surg.
Jour., 1904, pp. 651-654. Fly-specks may contain virulent
tubercular bacilli for at least fifteen days.
Mays, TuHos. J. The Fly and Tuberculosis. N.Y. Med. Jour.
& Phila. Med. Jour., 82, 1905, pp. 437-438. Believes that
J. O. Cobb’s data as given in Amer. Med. Jour. is not at all
conclusive.
NasH, J. C. T. A Note on the Bacterial Contamination of Milk
as Illustrating the Connection Between Flies and Epidemic
Diarrhea. Lancet, II, 1908, pp. 1668-69. Experiments show
that milk left exposed to flies soon contains many more germs
than that protected from them.
206 Insects and Disease
NasH, J. C. T. The A‘tiology of Summer Diarrhea. Lancet,
164, 1903, p. 330. Believes house-fly carries this disease be-
cause the two appear and disappear together.
ROBERTSON, A. Flies as Carriers of Contagion in Yaws. Jour.
Trop. Med. & Hyg., 11, 1908, No. 14, p. 213. As a result
of examinations the author concludes that the house-fly is
capable of carrying the virus of yaws.
SANDILANDS, J. E. Epidemic Diarrhea and the Bacterial Con-
trol of Food. Jour. Hyg., 6, 1906, pp. 77-92. Believes that
house-flies convey these diseases from the excrement of in-
fected infants.
SIBTHORPE, E. H. Cholera and Flies. Brit. Med. Jour., Sept.,
1896, p. 700. Flies considered scavengers, think they thus
help abate the disease.
SmitH, T. The House-fly as an Agent in Dissemination of In-
fectious Diseases. Amer. Jour. Pub. Hyg., Aug., 1908,
pp. 312-317. Points out that flies on account of their habits,
are dangerous sources of contamination.
SMITH, THEOBALD. The House-fly at the Bar. Merchants’
Assn., New York, 1909, pp. 1-48. Letters from various
authorities giving their opinion; quotations from various
authors. Bibliography.
VEEDER, M. A. Flies as Spreaders of Sickness in Camps. Med.
Record, 54, 1898, pp. 429-430. Flies feed on typhoid excreta
and pass to food. Cultures made from fly tracks and excreta
show many bacteria present.
VEEDER, M. A. The Relative Importance of Flies and Water
Supply in Spreading Disease. Med. Record, 55, 1899, pp. 10-
12. Reasons for believing that flies spread disease in many
instances. Burial of infected typhoid material no protection
but a menace.
Dangers from Flies. E. P. W. Nature, Vol. 29, pp. 482-483.
Review of an article by Dr. B. Grassi in regard to flies and
various diseases. Opthalmia is discussed. Flies may ingest
Bibliography 207
and pass unharmed eggs of various human parasites including
tapeworm.
HUMAN MYIASIS
ALLEN, CHAs. H. Demonstration of Locomotion in the Larvee
of the Gstride. Proc. Amer. Assn. Adv. Sct., Vol. 24, 1875,
pp. 230-236. Larve taken from flesh of child, one had moved
thirty-six inches and one six inches.
Frency, G. H. A Parasite the Supposed Cause of Some Cases
of Epilepsy. Canad. Ento., 32, 1900, pp. 263-264. Larve of
Gastrophilus or Dermatobia in the alimentary canal supposed
to have caused spasms in young boy.
GitBERT, N. C. Infection of Man by Dipterous Larve with
Report of Four Cases. Archives of Internal Med., Oct., 1908.
Historical; various kinds sometimes found in man; good
summary of subject. Bibliography.
Harrison, J. H. H. A Case of Myiasis. Jour. Trop. Med. &
Hyg., XI, Oct. 15, 1908, p. 305. Over 300 larvee of Lucilia
macellaria removed from face of negro woman.
HuMBERT, Frep. Lucilia macellaria Infesting Man. Proc. U.S.
Nat. Museum, 6, 1883, pp. 103-104. Records several cases
in which the screw-worm infested patients.
Jenyus, LEonarD. Tvans. Ento. Soc., London, Vol. II, 1839,
pp. 152-159. Notice of a case in which the larve of a dipterous
insect, supposed to be Anthomyia canicularis, Meig., were
expelled in large quantities from the human intestines.
KANE, E. R. A Grub Supposed to Have Traveled in the Human
Body. Insect Life, II, 1890, pp. 238-239. Larva of bot-fly
taken from face of boy. It had been traveling under the skin
for about five months.
McCampseELl, E. F., AND Cooper, H. J. Myiasis intestinalis
Due to Infection with Three Species of Dipterous Larve.
Jour. Amer. Med. Assn., 53, Oct. 9, 1909, pp. 1160-62. Gen-
208 Insects and Disease
eral notes on this subject and a report on a case in which
larve of three different species of flies were obtained from one
patient.
MEINERT, Fr. Lucilia nobilis Parasitic on Man. Insect Life,
II, 1892, pp. 36-37. Two larve from the ear of a man proved
to be the above species.
MourtTFELEDT, M. E. Hominivorous Habits of the Screw-worm
in St. Louis. Insect Lije, IV, 1891, p. 200. Many larve of
this species removed from the nasal passages of a patient.
NELSON, J. B. Insects in the Human Ear. Insect Life, VI, 1893,
p- 56. Two cases in which blow-fly larve are reported as
coming from the human ear.
RitEy, W. A. A Case of Pseudoparasitism by Dipterous Larve.
Canad. Ento., 38, 1906, p. 413. Several larve, species un-
determined, removed from back of patient.
Say, THomAs. On a South American Species of @strus Which
Inhabits the Human Body. Jr. Phil. Acad. Nat. Sci., Vol. 2,
1822, pp. 353-360. Extended notes on various dipterous
larve infesting man.
Snow, F. H. Hominivorous Habits of Lucilia macellaria ‘‘The
Screw-worm.” Psyche, 4, 1883, pp. 27-30. Cites observa-
tions made by himself and others.
WILLISTON, S. W. The Screw-worm Fly Compsomyia macellaria.
Psyche, 4, 1883, pp. 112-114. Notes on this species with a
- translation of a Spanish article by Anibalzaga in which in-
stances of this fly infesting human beings are recorded.
Yount, C. E., AND SUDLER, M. T. Human Myiasis from the
Screw-worm Fly. Jour. Amer. Med. Assn., Vol. 49, No. 23,
1907, p. 1912. Several cases giving reference to literature,
symptomatology, diagnosis.
STOMOXYS AND OTHER FLIES
AusTEN, E. E. Blood-sucking and Other Flies Known or
Likely to Be Concerned in the Spread of Disease. In Albutt’s
Bibliography 209
and Rolleston’s System of Med., 2, 1907, pp. 169-186. A
descriptive list of these flies. Bibliography.
AusTEN, E. E. Illustrations of African Blood-sucking Flies
Other Than Mosquitoes and Tsetse-flies. London, 1909.
NEwsTEAD, R. On the Life-history of Stomoxys calcitrans.
Jour. Econom. Biology, Vol. I, 1906, pp. 157-166. Describes
habits and life-history of larvee and adults. Important article.
STEPHENS, J. W. W., AND NEWSTEAD, R. The Anatomy of
the Proboscis of Biting Flies. Part II, Stomoxys. Ann. of
Trop. Med. & Parasit., Vol. I, No. 2, June 15, 1907, pp. 171-
182. Good anatomical paper. Part I (Glossina) was pub-
lished in mem. XVIII, 1906, Liverpool School Trop. Med.
Tuttock, F. Internal Anatomy of Stomoxys. Proc. Roy. Soc.,
‘London, 77, Series B, 1906, pp. 523-531. Descriptions and
drawings comparing with Glossina.
TSETSE-FLIES
AusTEN, E. E. A Monograph of the Tsetes-flies. Published by
order of the Trustees of the British Museum, 1903.
MANsON, P. Tsetse-flies. In Trop. Diseases, p.174. Descrip-
tion of genus; table of species; distribution; reproduction,
habits.
MIncHIN, E. A. Report of Anatomy of the Tsetse-fly (Glossina
palpalis). Proc. Roy. Soc., London, 76, Series B, 1905, pp. 531-
547. Good account of internal anatomy of this fly, important
because of its relation to trypanosomiasis.
Mincuin, E. A. The Breeding-habits of the Tsetse-fly. Nature,
Oct. 25, 1906, p. 636.
Mincuin, E. A., Gray, A. C. H., AND Tuttock, F. M. G.
(Sleeping Sickness Com.) Glossina palpalis in Its Relation
to Trypanosoma gambiense and Other Trypanosomes (Pre-
liminary Report). Proc. Roy. Soc., Vol. 78, 1906, pp. 242-258.
Report on certain experiments in feeding these flies on in-
210 Insects and Disease
fected animals and in allowing supposedly infected flies to
feed on various animals.
Novy, F. G. The Trypanosomes of Tsetse-flies. Jour. Injec.
Dis., III, 1906, pp. 394-411. Notes on the various species.
TRYPANOSOMES AND TRYPANOSOMIASIS
Bruce, Davip. Trypanosomiasis. Osler’s Mod. Med., Vol. I,
1907, p. 460. <A discussion of Trypanosoma lewisi, evanst,
brucet, gambienst, and the diseases caused by them.
Dutton, J. E., Topp, J. L., AND HaArrincton, J. W. B.
Trypanosome Transmission Experiments. Am. Trop. Med.
& Parasit., Vol. I, No. 2, June 15, 1907, pp. 201-229. Sec-
tions on attempts to transmit trypanosomes by tsetse-flies;
by other blood-sucking Arthropods, etc., conclude that try-
panosomes may be mechanically transmitted by the bite of
blood-sucking Arthropods.
Hooker, W. A. Descriptions of Certain Trypanosomes, and
Review of the Present Knowledge of the Réle of Ticks in the
Dissemination of Disease. Jour. Econ. Ento., Vol. I, No. 1,
1908, pp. 65-76. Good review, tables and literature.
Mincuin, E. A. Investigations on the Development of Try-
panosomes in Tsetse-flies and Other Diptera. Quart. Jour.
Micro. Sct., 1908, pp. 159-260.
MuscroveE, W. E., AND CLEGG, M. T. Trypanosomes and
Trypanosomiasis, with Special Reference to Surra in the Philip- ~
pine Islands. Bzological Lab., Bull. No. 5, Manila, 1903. Dis-
cuss flies, fleas, mosquitoes, lice and ticks as possible dissemi-
nators of the disease.
Novy, T. G., McNEAt, M. J., AND Torry, H. M. The Try-
panosomes of Mosquitoes and Other Insects. Jour. Injec.
Diseases, IV, 1907, pp. 223-276. These parasites often found
in mosquitoes and other insects. Bibliography.
NurraLL, G. H. F. The Transmission of Trypanosoma lewist
Bibliography 211
by Fleas and Lice. Parasitology, Vol. I, No. 4, Dec., 1908, pp.
296-301. This rat trypanosome is transmitted by fleas and lice.
Otp, J. E. S. Contribution to the Study of Trypanosomiasis
and to the Geographical Distribution of Some of the Blood-
sucking Insects, etc. Jour. Trop. Med. & Hyg., 12, Jan. 15,
1909, pp. 15-22. Notes on blood-sucking Dzptera and ticks.
RocGers, LEONARD. The Transmission of the Trypanosoma
evanst by House-flies and Other Experiments Pointing to the
Probable Identity of Surra of India and Nagana or Tsetse-fly
Disease of Africa. Proc. Roy. Soc., Vol. LXVIII, 1901,
pp. 163-170.
THimmu, C. A. Bibliography of Trypanosomiasis; embracing
original papers published prior to April 1909, and references
to works and papers on tsetse-flies. London, 1909.
Topp, J. L. A Note on Recent Trypanosome Transmission
Experiments. Jour. Trop. Med. & Hyg., 12, Sept., 1909,
p. 260. Show that they develop in G. palpalis when taken from
their mammal host at the proper stage of development.
Woopcock, H. M. The Hemoflagellates: a Review of Present
Knowledge Relating to the Trypanosomes and Allied Forms.
Quar. Jour. Micro. Sci., Vol. 50, 1906, pp. 151-331. Char-
acteristics; mode of infection; effects on host; biological con-
siderations; life-cycle, etc. Spirochacte; bibliography. Im-—
portant article.
Trypanosomiasis and Sleeping Sickness. Jour. Trop. Med. &
Hyg., II, pp. 146-147, 162, 179-180, 196. List of recent
literature.
SLEEPING SICKNESS
BAGSHAWE, A. G. Recent Advances in Our Knowledge of
Sleeping Sickness. Lancet, II, 1909, pp. 1193-97. A summing
up of the important discoveries of the preceding year.
HearsEy, H. Sleeping Sickness. Jour. Trop. Met. & Hyg.,
12, Sept. 1, 1909, pp. 263-264. Report on work accomplished
212 Insects and Disease
particularly in relation to the distribution of Glossina and other
biting flies.
Jarvis, C. Sleeping Sickness. Internat. Clinics, Vol. II, 1904,
pp. 37-44. Shows the relation of the tsetse-fly to this disease.
LANKESTER, E. R. The Sleeping Sickness. Quar. Review,
July, 1904, p. 113. Discovery and early history; the fly, the para-
site; other related parasites. Relation of parasites to their hosts.
MincHin, E. A. The Atiology of Sleeping Sickness. Nature,
Nov. 15, 1906, pp. 56-59.
Wo ttaston, A. F. R. Amid the Snow Peaks of the Equator:
a Naturalist’s Explorations Around Ruwenzori, with an
Account of the Terrible Scourge of Sleeping Sickness. Nat.
Geo. Mag., XX, No. 3, Mar., 1909. Abstracted from ‘‘From
Ruwenzori to the Congo” by above author.
Reports of the Sleeping Sickness Com. of the Royal Society,
I to IX, 1903 to 1908. Studies and experiments with the
trypanosomes and flies concerned in this disease. Later arti-
cles by this commission are to be found in the Pro. Royal Soc.,
Series B, LXXXI and LXXXII.
Sleeping Sickness Bureau Bulletins, 1 to 14, 1908-1910. Records
of studies and experiments with trypanosomes and tsetse-
flies, etc.
Transmission of Sleeping Sickness. Editorial in Jour. Amer.
Med. Assn., 53, Oct. 2, 1909, pp. 1104-05. Reviews recent
experiments and studies.
ROCKY MOUNTAIN FEVER AND TICKS
ANDERSON, J. F. Spotted Fever (Tick Fever) of the Rocky
Mountains. Hyg. Lab. Pub. Health and Mar. Hospt. Ser.,
Bull. 14, 1903. Distribution, etiology, etc. Believes that
ticks are responsible for the transmission of the disease.
Cootey, R. A. Preliminary Report on the Wood-tick. Bull. 75,
Mont. Ex. Sin., 1908. Sums up Ricketts’ finding; notes on
life-history in laboratory and field.
Bibliography 213
Kinc, W. W. Experimental Transmission of Rocky Mountain
Fever by Means of the Tick. Preliminary note. Pub. Health
and Mar. Host. Ser., 21, July 27, 1906, pp. 863-864. Con-
veyed this fever from one guinea-pig to another by means of
the tick.
Ricketts, H. T. The Transmission of Rocky Mountain Fever
by the Bite of the Wood-tick (Dermacentor occidentalis). Jour.
Amer. Med. Assn., Vol. 47, Aug., 1906, p. 358. Guinea-pig
successfully inoculated by means of tick.
Ricketts, H. T. The Rdle of the Wood-tick (Dermacentor
occidentalis) in Rocky Mountain Spotted Fever. Jour. Amer.
Med. Assn., Vol. 49, July 6, 1907, pp. 24-27. Notes on ex-
periments conducted and studies made. Takes position that
these experiments connect the tick with the transmission of
the fever.
Rosinson, A. A. Rocky Mountain Spotted Fever. Med. Rec.,
Nov. 28, 1908. Occurrence and distribution of the disease; re-
view of the various theories in regard to its transmission. P. E.
Jones of Salt Lake believes it is transmitted by mosquitoes.
Stites, C. W. A Zoological Investigation Into the Cause,
Transmission and Source of Rocky Mountain Spotted Fever.
Hyg. Lab. Pub. Health and Mar. Host. Ser., Bull. 20, 1905.
Does not find the parasite that had been recorded by others,
and finds no evidence to indicate that the ticks transmit the
disease.
Witsov, L. B., AND CHANNING, W. M. Studies in Pyroplasmosis
hominis (Spotted Fever or Tick Fever of the Rocky Moun-
tains). Jour. Injec. Diseases, 1, 1904, pp. 31-57. Evidence
that the disease is transmitted solely by means of the ticks.
TICKS AND VARIOUS DISEASES
Banks, NATHAN. ‘Tick-borne Diseases and Their Origin. Jour.
Eco. Ento., Vol. I, No. 3, 1908, pp. 213-215. Shows how
214 Insects and Disease
ticks may become important disease-carriers by changing their
hosts as the normal host is exterminated, or for other reasons.
BANKS, NATHAN. A Revision of the Ixodoidea or Ticks of the
United States. Tech. Series No. 15, Bull. of Bureau of Ento.,
U.S. Dept. Agric., 1908. Structure, life-history, classification,
catalogue, bibliography.
BARBER, C. A. The Tick Pest in the Tropics. Nature, 52,
1895, pp. 197-200. Direct and indirect effects of ticks on
their hosts.
Curisty, C. Ornithodoros moubata and Tick Fever in Man.
Brit. Med. Jour., Vol. II, 1903, p. 652. Relation of the tick
to Filaria perstans.
Dutton, J. E., AND Topp, J. L. The Nature of Human Tick
Fever in the Eastern Part of the Congo Free State with Notes
on the Distribution and Bionomics of the Tick. Liverpool
School of Tropical Medicine. Memoir, 17, Nov., 1905, pp. 1-18.
Hooker, W. A. A Review of the Present Knowledge of the Réle
of Ticks in the Transmission of Disease. Jour. Eco. Ento.,
Vol. I, No. 1, 1908, p. 65. Review of the subject; table show-
ing zoological position of parasites transmitted by ticks.
Table showing zoological position of ticks.
Hooker, W. A. Life-history, Habits and Methods of Study of
the Ixodoidea. Jour. Eco. Ento., Vol. I, No. 1, 1908, p. 34.
Notes on several species, especially M. annulatus. Host re-
lationship; adaptations as factors in host relationship; mating;
geographical distribution; methods of breeding, etc.
Hooker, W. A. Some Host Relations of Ticks. Jour. Eco.
Ento., Vol. 2, No. 3, 1909, p. 251. Notes on ticks found on
various hosts.
Hunter, W. D., AND Hooker, W. A. Information Concern-
ing the North American Fever Tick with Notes on Other
Species. Bull. 72, Bureau of Ento., 1907. Life-history, host
relation, etc., of fever tick; classification and notes on other
species; bibliography divided into sections.
4
B33
bi
yy
Bibliography 205
Lounspury, C. P. Habits and Peculiarities of Some South
African Ticks. Rept. of the Brit. Assn. for the Advancement of
Sci., 1905 (South Africa), pp. 282-291.
McCrakE, THomas. Relapsing Fever. Osler’s Mod. Med.,
Vol. II, p. 245, 1907. Etiology, symptoms, treatment, etc.
(Apparently communicated by blood-sucking insects.)
NEWSTEAD, R. On the Pathogenic Ticks Concerned in the
Distribution of Diseases in Man. Brit. Med. Jour., II, 1905,
pp. 1695-97. Classification and habits, particularly of Orni-
thodoros moubata.
NuTTatL, G. H. F. The Ixodoidea or Ticks. Jour. of Roy.
Inst. of Pub. Health, 1908. List of disease-bearing ticks.
Position of ticks, classification. Biology. Preventive measures.
NutTTatL, G. H. F. Piroplasmosis. Jour. Roy. Inst. of Pub.
Health, 1908. What piroplasma are; diseases produced by
them. Biology.
NuTTALL, GEO. F., and co-workers. Canine Piroplasmosis,
Parts Ito VI. Jour. Hyg., Vol. 4, No. 2, Apr., 1904, to Vol. 7,
No. 2, Apr., 1907. A thorough discussion of the disease, the
parasite which causes it and the ticks which convey it.
Pocock, R. I. Ticks. In Albutt and Rolleston’s System of
Med., II, 1907, pp. 187-203. Classification; description of the
best-known pathogenic species. Extended bibliography.
SKINNER, B. Preliminary Note on Ticks Infecting the Rats
Suffering from the Plague. Brit. Med. Jour., Vol. II, 1907,
p. 457. Records taking tick on a plague-sick rat and finding
bacilli similar to plague bacilli in connection with it.
SMITH, T., AND KitBorNE, F. L. Texas Fever. U. S. Dept.
Agric. Bureau of Animal Industry, Bull. No. 1, 1893. Records
of the experiments showing disease to be transmitted by
ticks.
WELLMAN, F. C. Preliminary Note on Some Bodies Found in
Ticks—Ornithodoros moubata—Fed on Blood Containing
Embryos of Filaria. Brit. Med. Jour., July 20, 1907, p. 142.
216 Insects and Disease
Believes that F’. perstans is conveyed from man to tick and
from tick to man.
KALA-AZAR AND BEDBUGS
GIRAULT, A. A. The Indian Bedbug and Kala-azar Disease.
Sct., N. S., Vol. XXV, 1907, p. 1004. Indian bedbug is
C. rotundatus Sig. Its distribution. Summary of Dr. Patton’s
paper on ‘“‘Preliminary Report on the Development of the
Leishman-Donovan Body in the Bedbug.”
Patton, W. S. The Development of the Leishman-Donovan
Parasite in Cimex rotundatus. Scientific Mem. of Gov. of
India, Nos. 27 and 31, 1907. ‘Traces the development of this
parasite; believes that the bedbug is concerned in transmitting
this disease.
See also Manson’s Tropical Diseases, pp. 178-190.
TEXT OR REFERENCE BOOKS IN WHICH THE RE-
LATION OF INSECTS TO VARIOUS DISEASES IS
DISCUSSED
Aspott, A. C. Hygiene of Transmissible Diseases. Phil.,
1899. Causes, modes of dissemination, prevention, treatment
of infectious and contagious diseases.
AtLBuTT, T. C., AND RottestTon, H. D. A System of Medicine.
London, 1907. Vol. II, Pt. II, contains sections on tropical
diseases; animal parasites and the diseases they carry and
zoological articles dealing with Protozoa, mosquitoes, flies and
ticks. All articles have bibliographies, some of them quite
extensive.
BALFouR, ANDREW. Review of Recent Advances in Tropical
Medicine. Supplement to Third Rept. Wellcome Research Lab.,
London, 1908. Notes, extracts and references in regard to
important articles during the preceding few months.
Se 3
Bibliography 27
DantEts, C. W. Studies in Laboratory Work, 2d ed., London,
1907. A good discussion of animal parasites in the blood and
blood-plasma; development of malarial parasites in mosquitoes;
flies, fleas, lice, bedbugs, ticks, etc.
Jackson, C. W. ‘Tropical Medicine. Phil., 1907. Discusses
diseases due to bacteria and the parasites and uncertain
causes. Splendid recent summary of the various ways in
which the different diseases are disseminated.
LANGFELD, MILLARD. Introduction to Infectious and Parasitic
Diseases, Including Their Causes and Manner of Transmis-
sion. Phil., 1907. Chapters on infection, animal parasites,
avenues of exit and portals of entry of infectious agents and
parasites into the body.
Manson, Patrick. Lectures on Tropical Diseases. London,
1905. Delivered at Cooper Medical College, 1905. Dis-
cusses several of these diseases. Last chapter on problems
in tropical medicine.
Manson, Patrick. ‘Tropical Diseases. London, 1907, Dis-
eases of the tropics discussed in a very comprehensive manner.
Considerable attention given to the part played by insects in
the transmission of many of the diseases.
METcHNIKOFF, E. Immunity in Infectious Diseases. (Trans.
from the French by F. G. Binnie.) Cambridge, 1905. Splendid
discussion of various kinds of immunity. Insects referred to
occasionally.
OstER’s Modern Medicine. Vol. I, 1907, Pt. VI, Diseases Caused
by Protozoa. Part VII, Diseases Caused by Animal Parasites.
Vol. II, 1907, Infectious Diseases. Vol. III, Infectious Diseases
(cont.). One of the best and most modern text-books; the
volumes noted above contain many references to the relation
of insects to the particular diseases under discussion.
Park, W. H. Pathogenic Micro-organisms, Including Bacteria
and Protozoa. N. Y., 1908. ‘These organisms comprehensively
treated.
218 Insects and Disease
RickETTs, H. T. Infection, Immunity and Serum Therapy.
Chicago, 1906. Chapters on parasitism, infection, contagion,
immunity, various diseases, etc.
SCHEUBE, B. The Diseases of Warm Countries: a Handbook
for Medical Men. ‘Trans. from Ger. by Pauline Falcke,
London, 1903. Sections on general infectious diseases, diseases
caused by animal parasites, etc. Good bibliography of each
disease treated.
Stmpson, W. J. R. The Principles of Hygiene as Applied to
Tropical and Subtropical Climates. London, 1908. Occa-
sional references to flies and mosquitoes as carriers of disease.
Chapter XV deals with malaria and other diseases caused by
mosquitoes.
Witson, J. C. Modern Clinical Medicine; Infectious Diseases.
New York and London, 1905. Chapters on yellow fever,
malarial diseases and plague; contains references to the rela-
tion of insects to these diseases.
MISCELLANEOUS ARTICLES
Batrour, ANDREW. Further Observations on Fowl Spiroche-
tosis. Jour. Trop. Med. & Hyg., 12, Oct. 1, 1909, pp. 285-
289. ‘Ticks and lice may carry this disease.
CHITTENDEN, F. H. Harvest-mites or ‘‘Chiggers.” Cuzrcular 77,
U. S. Dept. Agric. Bur. Ento., 1906, pp. 1-16. Descriptions
of these pests and their habits. Remedies.
Doty, A. H. The Means by Which Infectious Diseases Are
Transmitted. Amer. Jour. of Med. Sct., 138, July, 1909, pp. 30-
39. Flies and mosquitoes as disseminators of disease briefly
discussed.
Duncan, F. M. Industrial Entomology: the Economic Im-
portance of a Study of Insect Life. Jour. Roy. Soc. Arts,
May 22, 1908, pp. 688-696. A very interesting review of the
subject of insects and disease.
ip
!
i
'
Bibliography 219
FLEXNER, SIMON. Science, N. S., Vol. 27, No. 682, Jan. 24,
1908, pp. 133-136. On these pages the author discusses
relation of bacteria and Protozoa to human diseases.
GOLDBERGER, JOS., AND SHAMBERG, J. F. Epidemic of an
Utricaroid dermatitis Due to a Small Mite (Pediculoides ventri-
cosus) in the Straw of Mattresses. Pub. Health Rept., Pub.
Health and Mar. Hospt. Ser., July 9, 1909, Vol. XXIV, No. 28.
Experiments showed that a certain skin disease occurring
during summer was due to this mite. |
Gorcas, W. C. The Part Sanitation Is Playing in the Con-
struction of the Panama Canal. Jour. Amer. Med. Assn., 53,
Aug. 21, 1909, pp. 597-599. Shows the changes that have
been brought about by modern sanitation and the destroying
of the mosquitoes’ breeding-places.
Howarp, L. O. MHydrocyanic-acid Gas Against Household
Insects. Circular 46, U. S. Dept. Agric., Div. of Ento., 1902.
Directions for handling this dangerous gas.
Kinc, A. F. G. Insects and Disease; Mosquitoes and Malaria.
Pop. Sci. Mo., XXIII, 1883, pp. 644-658. Extended article
in which the author sums up the observations which led him
to believe that malaria and other diseases were transmitted
by the mosquito. One of the earliest articles on this subject;
refers to an article in New Orleans Med. & Surg. Jour.,
Vol. IV, 1848, pp. 563-601, by Josiah Nott, who maintained
that yellow fever was carried by mosquitoes.
Manson, Patrick. Recent Advances in Science and Their
Bearing on Medicine and Surgery. Jour. Trop. Med. & Hyg.,
XI, pp. 337-338, Sept. 16, 1908. Discussion of parasites and
disease and their methods of dissemination.
NEWSTEAD, R., Dutton, J. E., AND Topp, J. L. Insects and
Other Arthropoda Collected in the Congo Free State. Amn.
Trop. Med. & Parasit., Vol. 1, No. 1, Feb. 1, 1907, pp. 3-100.
An interesting paper giving notes on many insects that cause
or carry disease.
220 Insects and Disease
NuttTaL.L, G. H. F. Spirochztosis in Man and Animals. Jour.
of Roy. Inst. of Pub. Health, 1908. Why Spirochetes should
be regarded as Protozoa. Classification; list of blood-inhabiting
forms; relapsing fevers; transmission by ticks and other
Arthropods.
O’ConnELL, M. D. The Oversea Transport of Insect-borne
Disease. Jour. Trop. Med. & Hyg., XI, 43, Feb. 1, 1908.
Refers to article in same journal (Jan. 15) and points out that
malaria is very likely to be transmitted by mosquitoes in this way.
OsBoRN, HERBERT. Insects Affecting Domestic Animals.
U.S. Dept. of Agric., Div. of Ento., Bull. No. 5, N. S., 1896.
Discusses the various insect pests of man and domestic animals
Host lists. Bibliography.
Rickets, H. T., and WILDER, R. M. The Typhus Fever of
Mexico. Jour. Amer. Med. Assn., LIV, No. 6, Feb. 5, 1910,
p. 463. Believes this disease is transmitted by insects, probably
lice.
RITCHIE, JAMES. A Review of Current Theories Regarding
Immunity. Jour. Hyg., 2, 1902, pp. 215-285, and pp. 452-
464. Discussion of various theories. Bibliography.
SHIPLEY, A. E. On the Relation of Certain Cestode and Nema-
toda Parasites to Bacterial Disease. Jour. of Eco. Biol., 4,
1909, pp. 61-71. Shows that these parasites may often cause
serious diseases by opening the way for malignant germs.
Warp, H. B. Spirochetes and Their Relationship to Other
Organisms. Amer. Nat., 42, 1908, No. 498, pp. 374-387.
Still undecided as to whether they belong with bacteria or
Protozoa, probably the latter.
Warp, H. B. The Relation of Animals to Disease. Science,
N. S., 22, 1905, pp. 193-203. An interesting, comprehensive
review of the subject.
Warp, Henry B. Relation of Animals to Disease. Transactions
of Amer. Micro. Soc., Vol. 27, 1907, pp. 5-20. ‘The various
ways in which animals may produce or carry disease.
Bibliography 221
The Oversea Transport of Insect-borne Diseases. Editorial in
Jour. Trop. Med. & Hyg., XI, Jan. 15, 1908, pp. 22-23.
Points out the danger of yellow fever, plague and other diseases
being borne overseas by infected insects.
The Society for the Destruction of Vermin. Editorial in Jour.
Trop. Med. & Hyg., XI, Apr. 15, 1908, p. 124. Tells of or-
ganization of such society and its purposes.
INDEX
INDEX
Adams, S. H., 132.
Advisory Committee, 146.
Agramonte, Dr. Aristides, 123.
Alimentary canal, fly larve in, 49.
Ameeba, 19.
Anopheles, adults, 91; eggs, 92;
habits of adults, 94; larve, 78,
79, 93; pup, 93; resting po-
sition, 92; species in U. S., 92.
Anthrax, 44; and flies, 70.
Arthropoda, 26.
Asexual reproduction, 111.
Bacillus, anthracis, 44; icteroides,
B24; lepre, 171; pestis, 150.
Bacillus carriers, 66.
Back-swimmers, 100.
Bacteria, 15; saprophytic and
parasitic, 17; effect on host,
18; dissemination, 18.
Bedbugs, 54, 147.
Banks, Nathan, 34.
Bell-animalcule, 22.
Berne, 51.
Birds as enemies of mosquitoes,
99-
Black-flies, 46.
Black-heads, 35.
Blow-flies, 48.
Blue, Dr. Rupert, 143.
Blue-bottle flies, 48.
Bot-flies, 50.
Break-bone fever, 169.
Breeze-fly, 44.
Buffalo-gnats, 46.
Calliphora vomitoria, 48.
Camphor, for mosquitoes, 102.
Cancer, 36.
Carroll, Dr. James, 123.
Castor-bean tick, 27.
Cattle tick, 29.
Cedar oil, for mosquitoes, 102.
Ceratophyllus, faciatus, 153; acu-
tus, 156.
Cesspools, 72.
Chigger, 53.
Chigger-flea, 53.
Chigo, 30, 39.
Chigoe, 53.
Cholera, 68.
Chrysomyia macellaria, 47.
Cimex, lectularis, 54; rotunda-
tus, 173.
Contagious diseases, 8.
Conjugation, 20.
Cooley, Prof. R. A., 33:
Craig, Dr. C..F., 118.
Ctenocephalus, canis, 154; felis,
154.
Culex, fatigans, 96, 170; pipiens,
98.
223
224
Dengue, 169.
Dermatobia cyaniventris, 51.
Dermatophilus penetrans, 53.
Diarrhea, 69.
Diptera, 43.
Diving beetles, roo.
Dragon-flies, 99.
Dysentery, 20.
Eggs, of flies, 63; of mosquitoes,
77; of Anopheles, 92.
Egyptian opthalmia, 52.
Elephantiasis, 164.
Enemies of mosquitoes, 97.
Enteritis, 69.
Euglena, 21.
Eye-worm, 12.
Face-mite, 35.
Fighting mosquitoes, adults, ror;
larve, 103.
Fiji Islands, Anopheles in, 117.
Filaria bancrofti, 164.
Finlay, Dr. Charles, 124.
Fish, roo.
Flagella, 20.
Fleas, 52; and plague, 142, 145,
147; structure and habits, 151;
common species, 153; on
ground squirrels, 156; reme-
dies for, 157.
Flies, 43; and typhoid, 65;
specks, 66; and various dis-
eases, 68.
Flesh-flies, 48.
Fumigating for mosquitoes, 102.
Gad-fly, 43.
Index
Glossina palpalis, 163.
Golgi, Camillo, rog.
Grassi, Prof. G. B., 118.
Gray-flies, 47.
Ground squirrels and plague,
TSR.
Guinea-worm, II.
Hemameeba, 109.
Hematobia, 45.
Hemosporidiida, 24.
Hemotopinus spinulosis, 55.
Harvest-mite, 37.
Havana, yellow fever in, 131.
Hawaii, mosquitoes in, 98.
Hemiptera, 54.
Homalomyia canicularis, 49.
Hoplopsyllus anomalus, 156.
Horse bot-flies, so.
House-flies, 57; structure, 59;
how they carry bacteria, 62;
life-history and habits, 63;
fighting, 71; and_ typhoid,
65.
Horse-flies, 43.
Howard, Dr. L. O., 59, 73.
Hyperparasitism, 3.
Immunity, 5.
Indian Plague Commission, 144.
Infectious diseases, 8.
Infusoria, 22.
Insects, cause or carry disease,
40; numbers, 40; annual loss
caused by, 41; how they carry
disease germs, 55.
Irrigating ditches, 104.
Itch-mite, 36.
Index
Jackson, Dr. D. D., 67
Jennings, 22.
Jiggers, 38, 53.
Jigger-flea, 53.
Kala-azar, 173.
Kerosene, 104.
Koch, 44.
Lamprey-eel, 2.
Lancisi, J. M., 107.
Larve, of flies, 64; of mosqui-
toes, 78.
Laveran, A., 108.
Laverania, 109.
Lazear, Dr. Jessie W., 123.
Leeuwenhock, Anton
22.
Lepra bacillus, 36.
Leprosy, 36, 70, I71.
Lice, 54.
Linneus, 76.
Little house-fly, 49.
Lock-jaw, 18.
Loemopsylla cheopus, 153.
Low, Dr. A., 118.
Lucilia spp., 48.
Lugger, Prof. Otto, 38.
von,
Malaria, early theories in regard
to, 106; parasite that causes,
108; life history of parasite,
109; parasite in mosquito, 113;
summary, 117; experiments,
118.
Maggots, 63.
Malta or Mediterranean fever,
171.
225
Mange, 37.
Manure-fly, 59.
Manson, Sir Patrick, 112,
123.
Mastigophora, 20.
Melanin, rro.
Micrococcus melitensis, 171.
Microbes, Io.
Mites, 26, 35.
Mouth-parts, of fly, 60; of mos-
quito, 83.
Mosquito, 76; abdomen, 86;
adults, 81; Anopheles, o1;
how they bite, 84; effect of
bite, 87; blood, 90; how they
breathe, 89; classification, 91;
and dengue, 169; eggs, 77;
and elephantiasis, 164; ene-
mies, 77; fighting, adults, ror,
larve, 103; larve, 78; and
malaria, 106; malarial para-
site in, 113; mouth-parts, 83;
other species, 96; pupz, 80;
salivary glands, 87; thorax, 85;
and yellow fever, 94, 120.
Mus, norvegicus, 154; rattus,
154.
Nanga, 45.
Nematodes, 164.
New Orleans, yellow fever in,
120, 132.
Noctiluca, 21.
No-see-ums, 46.
Ochromyia anthropophaga, 49.
Oil of citronella, 102.
Oil of pennyroyal, 102.
226
Oriental sore, 174.
Ornithodorus moubata, 34.
Oscinide, 52.
Otospermophilus beecheyi, 155.
Ox-warbles, 50.
Panama Canal zone, 135.
Paramcecium, 22.
Parasite, defined, 1; classes of,
4; in new regions, 5; diseases
caused by, 7; effect on host, 9;
relation to host, 14.
Parasitism, 3.
Pasteur, L., 44.
Pearls, 13.
Piroplasma bigeminum, 29.
Plague, early history of, 142;
fleas that transmit, 153; and
flies, 70; and ground squirrels,
I55; how combatted in San
Francisco, 143; results of
other investigations, 150; Ver-
jbitski’s experiments, 147;
work of Indian Plague Com-
mission, 146.
Plasmodium, 109. |
Protozoa, 19; classes of, 20.
Proboscis, of fly, 60; of mos-
quito, 80.
Privies, 72.
Privy-fly, 59.
Pseudopodia, 20.
Psoroptes communis, 37.
Pulex irritans, 154.
Punkies, 46.
Pupe, of house-flies, 64; of
mosquitoes, 8o.
Pyrethrum, 102.
Index
Rats, and plague,
species of, 154.
Red-bugs, 38.
Reed, Dr. Walter, 123.
Relapsing fever, 21, 33.
Rhizopoda, 20.
Ricketts, Dr. H. Fj 32
Rio de Janeiro, yellow fever in,
137.
Rocky Mountain spotted fever,
22.
Ross, Ronald, 112.
Rucker, Dr. W. C., 143.
143, 1453
Sacculina, 2.
Salivary glands, 84, 87.
Salt marshes, 97, 105.
Sambon, Dr. L. W., 118.
Sand-fleas, 53.
Saprophytic bacteria, 17.
Sarcophaga spp., 48.
Sarcoptes scabiei, 37.
Scab, 37.
Screw-worm, 47.
Seed-ticks, 27, 30.
Sheep bot-flies, 51.
Simmond, Dr. P. L., 145.
Siphonaptera, 52.
Skinner, Dr. H., 159.
Sleeping sickness, 21, 161.
Slipper animalcule, 22.
Small-pox, 70.
Smith, Dr. Theobald, 29.
Smudges, 102.
Sore-eye, 52.
Spiders, 26.
Spiracles, 89.
Spirocheta, 21, 130.
Index
Spore formation, 24.
Spores, 24.
Sporozoa, 22.
Spotted fever, 32.
Stable-fly, 44, 75.
Stegomyia, calopus, 94, 98, 139
scutellaris, 96.
Sticklebacks, ror.
Stomoxys calcitrans, 44.
Sulphur, ro2.
Surra, 45.
‘Tabanus, 45.
Tahiti, mosquitoes in, 96.
‘Tapeworms, 2.
Tetanus, 18.
Texas fever, 28.
Theobald, Dr. F. V., 76.
Ticks, 26.
Tidewater minnows, 101.
‘Tobacco smoke, 102.
‘Top-minnows, 98, 101.
Torcel, 51.
Trachee, 89.
Tracheal gills, 79.
Trichina, 2.
Trypanosome, 45, 161.
‘Trypanosoma, evansi, 45; brucei,
45; lewisi, 162; gambiensi, 162.
227
Tsetse-fly, 45, 163.
Tubercular bacilli, 69; germs,
69.
Typhoid-fly, 57> 59:
Vaughan, Dr. W. C., 67.
Ver macque, 51.
Verjbitski, D. T., 147.
Vorticella, 22.
Water-boatmen, 100.
Water-troughs, 104.
Whip-bearers, 20.
Whirligig beetles, too.
White, Surgeon J. H., 134.
Wrigglers, 78.
Yellow fever, 120; Commission,
123; early observations on,
121; experiments, 125; danger
of in Pacific Islands, 140; in
Havana, results of work on,
131; history of in United
States, 120; mosquito, 94;
habits of, 95; in Panama
Canal zone, 135; in Rio de
Janeiro, 137; summary of re-
sults of work on, 129.
THE AMERICAN NATURE SERIES
In the hope of doing something toward furnishing a series where
the nature-lover can surely find a readable book of high authority,
the publishers of the American Science Series have begun the publi-
cation of the American Nature Series. It is the intention that in its
own way, the new series shall stand on a par with its famous prede-
cessor.
The primary object of the new series is to answer questions
which the contemplation of Nature is constantly arousing in the
mind of the unscientific intelligent person. But a collateral object
will be to give some intelligent notion of the ‘‘causes of things.”’
While the codperation of foreign scholars will not be declined,
the books will be under the guarantee of American experts, and gen-
erally from the American point of view; and where material crowds
space, preference will be given to American facts over others of not
more than equal interest.
The series will be in six divisions :
I. NATURAL HISTORY
This division nill consist of two sections.
Section A. A large popular Natural History in several vol-
umes, with the topics treated in due proportion, by authors of un-
questioned authority. 8vo, 7$x10¢ in.
The books so far publisht in this section are:
FISHES, by Davin Srarr Jorpay, President of the Leland Stanford
Junior University. $6.00 net; carriage extra.
AMERICAN INSECTS, by Vernon L. Kettoee, Professor in the
Leland Stanford Junior University. $5.00 net; carriage extra.
BIRDS OF THE WORLD. A popular account by Franx H.
Kwowtron, M.S., Ph.D., Member American Ornithologists
Union, President Biological Society of Washington, etc., etc.,
with Chapter on Anatomy of Birds by Freperic A. Lucas,
Chief Curator Brooklyn Museum of Arts and Sciences, and edited
by Rosertr Rineway, Curator of Birds, U. S. National Museum.
$7.00 net; carriage extra.
Arranged for are:
SEEDLESS PLANTS, by Georer T. Moore, Head of Department
of ony Marine Biological Laboratory, assisted by other spe-
cialists.
WILD MAMMALS OF NORTH AMERICA, by C. Harr Mer-
riaM, Chief of the United States Biological Survey.
REPTILES AND BATRACHIANS, by Leonnarp STESNEGER,
Curator of Reptiles, U. S, National Museum.
1
AMERICAN NATURE SERIES (Continued)
I. NATURAL HISTORY (Continued)
Section B. A Shorter Natural History, mainly by the Authors
of Section A, preserving its popular character, its proportional treat-
ment, and its authority so far asthat can be preserved without its
fullness. Size not yet determined.
II. CLASSIFICATION OF NATURE
1. Library Series, very full descriptions. 8vo. 74x10 in.
Already publisht:
NORTH AMERICAN TREES, by N. L. Brirrton, Director of the
New York Botanical Garden. $7.00 net; carriage extra.
FERNS, by Campsect E. Waters, of Johns Hopkins University,
$3.00 net; by mail, $3.30.
2. Pocket Series, Identification Books—‘‘ How to Know,”’ brief and
in portable shape.
Ill. FUNCTIONS OF NATURE
These books will treat of the relation of facts to causes and
effects—of heredity and the relations of organism to environment.
Svo. 68x8% in.
Already publisht:
THE BIRD: ITS FORM AND FUNCTION, by C. W. Beese,
Curator of Birds in the New York Zoological Park. $3.50 net;
by mail, $3.80.
Arranged for:
THE INSECT: ITS FORM AND FUNCTION, by Vernon L.
Kettoae, Professor in the Leland Stanford Junior University.
THE FISH: ITS FORM AND FUNCTION, by H. M. Smrcu, of
the U. S. Bureau of Fisheries.
IV. WORKING WITH NATURE
How to propagate, develop, care for and depict the plants and
animals. The volumes in this group cover such a range of subjects
that it is impracticable to make them of uniform size.
Already publisht:
NATURE AND HEALTH, by Epwarp Curtis, Professor Emeritus
in the College of Physicians and Surgeons. 12mo. $1.25 net;
by mail, $1.37.
THE FRESHWATER AQUARIUM AND ITS INHABITANTS.
A Guide for the Amateur Aquarist, by Orro Eccrtine and
FREDERICK ExnrengeRG. Large 12mo. $2.00 net; by mail, $2.19.
2
AMERICAN NATURE SERIES (Continued)
IV. WORKING WITH NATURE (Continued)
THE LIFE OF A FOSSIL HUNTER, by Cuanrtes H. Srernsere.
Large 12mo. $1.60 net; by mail, $1.72.
SHELL-FISH INDUSTRIES, by James L. Kettoae, Professor
in Williams College. Large 1%mo. $1.75 net; by mail, $1.93.
THE CARE OF TREES IN LAWN, STREET AND PARK, by
B. E. Frrnow, Professor of Forestry, University of Toronto.
Large 12mo. $2.00 net; by mail, $2.17.
HARDY PLANTS FOR COTTAGE GARDENS, by He ten R.
A.BEE. Large 12mo. $1.60 net; by mail, $1.73.
{INSECTS AND DISEASE, by Rennie W. Doane, Assistant Pro-
fessor in the Leland Stanford Junior University. $1.50 net;
by mail, $1.62.
Arranged for:
PHOTOGRAPHING NATURE, by E. R. Sanzorn, Photographer
of the New York Zoological Park.
CHEMISTRY OF DAILY LIFE, by Hewry P. Tarot, Professor
of Chemistry in the Massachusetts Institute of Technology.
V. DIVERSIONS FROM NATURE
This division will include a wide range of writings not rigidly
systematic or formal, but written only by authorities of standing.
Large 12mo. 54x84 in.
Already publisht:
eam by Vernon L. Kettoae. $1.50 net; by mail,
FISH STORIES, by Cuartes F. Hotper and Davin Srazr JorpDan.
$1.75 net; by mail, $1.87.
Arranged for:
BIRD NOTES, by C. W. Breese.
VI. THE PHILOSOPHY OF NATURE
A Series of volumes by President Jorpan, of Stanfora Univer-
sity, and Professors Brooks of Johns Hopkins, Lut of Yale, THom-
son of Arberdeen, Przisram of Austria, zur Strassen of Germany,
and others. Edited by Professor Ketioee of Leland Stanford. 12mo.
54x74 in.
Arranged for:
THE STABILITY OF TRUTH, by Davin Stanr Jorpan.
HENRY HOLT AND COMPANY, New York
January, "11. :
AMERICAN INSECTS
By VERNON L. KELLOGG
PROFESSOR IN LELAND STANFORD, JR., UNIVERSITY
ITH 812 figures and 11 colored plates; 647 pp.
(American Nature Series, Group 1); $5.00 net
(postage 34 cents). Students’ edition, $4.00.
comprehensive account of the natural history of the in-
sects of America, written simply yet seriously, so as to
be acceptable to the general reading public as well as to
professional students of nature. Allof the insect orders
represented in our country are treated in this single
volume, which, despite its comprehensiveness and its
profusion of illustrations, is so compactly made as to be
in no way unwieldy. The book may be used for con-
tinuous reading by those wishing to inform themselves
concerning the kinds and habits of American insects in
general, or as a reference manual for authoritative in-
formation on classification, specific remedies for certain
pests, special discussions of structural, physiological, or |
ecological phases of insect biology, etc.
“Certain to be widely useful . . . readable and profusely illus-
trated. It gives a great amount of information about the insects
of this country, in such a manner that it is available to any intel-
ligent person ... other works are necessary for particular pur-
poses ; but if I were asked to name a single work for a beginner,
who at the same time meant business, I should not hesitate to
recommend this new product of Stanford University.”—7Z. D. A.
Cockerell in The Dial.
‘*Nothing needed to make this a complete he to the study of
our American insects has been omitted.’’—M/. A. Bigelow in the
Independent.
“Professor Kellogg’s volume will be welcomed as one of the
pect general text-books on the subject covered.”—C. L. Marlatt
én Sctence.
““The work is scientifically conceived and carefully executed
in every part; but it is free from all unnecessary technicalities
and so fresh in its spirit and so informal in its tone that one
scarcely remembers in reading it the scientific attainments of its
eminent author. It is a storehouse of biological information
drawn from authoritative sources and vivified by contributions
from the author’s own rich experience as an observer and an in-
vestigator. ... The style is vivacious, flowing, correct, as pel-
lucid as a mountain brook, and free from all those affectations of
sprightliness or sentiment which seem likely to become conven-
isi in the literature of nature study.”—S. A. Forbes in School
Czence.
‘‘An excellent work, and we can heartily recommend it to all
who are interested in the classification and natural history of in-
sects. It is written in an agreeable and attractive style and can
be referred to anywhere by the ordinary reader without fear of
being disheartened by purely technical language ... the greater
part of the large volume is clear and simple and most interestin
to every Nature Student. ... No onecan take up the book an
open it anywhere without becoming deeply interested in the sub-
ject treated of, whatever it may be, provided, that is, that he has
any love at all for living creatures, any interest in the myriad
forms and modes of life of these wonderful beings that are
everywhere about us.” —Canadian Entomologist.
** Sumptuous, delicate, exquisite, these are the words that easily
leap to our lips in looking through the book. But I cannot too
much emphasize the fact that in the volume we also have science
made thoroughly readable.”—£. P. Powellin Unity.
“Is probably the most valuable handbook of the subject for
the technical student or amateur collector.”—Aansas Farmer.
‘“*Hin ebenso reichhaltiges wie luxurids ausgestattetes Werk
zur Einftihrung in das Studium der Biologie der amerikanischen
Insekten.”—dm. Rettter in Wiener Ent. Zettung.
‘*The book is of the first importance in its class.”—Out West.
“This work easily ranks as the most comprehensive volume
treating of American insects yet produced.... The subject-
matter is presented in an easy narrative style, though accuracy
is not sacrificed for the sake of popularity. ... The volume ex-
hibits a thorough appreciation of and familiarity with recent in-
vestigations. ... This work brings together in one volume a
vast amount of information and the author is to be congratulated
upon having produced a very readable, comprehensive work,
which should prove attractive and exceedingly helpful to the
amateur as well as essential to every investigator.” —Z£. P. Felt
zn Psyche.
‘We have in this single volume a whole library of insect lore.”
—lV. Y. Critic.
“Es ist ein gewaltiges Unternehmen, das Verf. in diesem
Werke zur Durchfiihrung gebracht hat und die vollendete Art
und Weise dieser Durchftihrung dtirfte dem Buche in seinem
Vaterlande einen vollen Erfolg sichern. Es will seinen Lesern
eine Uebersicht iiber die gesammte Insektenwelt geben,aber nicht
in dem oberflachlichen Feuilletonstil, den man in derartigen
Werken hadufig findet, sondern mit wirklichen wissenschaft-
Ficher Griindlichkeit, und das ist dem Verfasser vorztiglich
gelungen.”—Zeztschr. fur wissenschaftliche Insektenbiologie.
‘“* The work is probably the best that exists for anyone desiring
an introductory work on North American insects compressed
into a single volume.”—David Sharp in Nature.
‘We are glad to see the interesting chapter on insects and dis-
ease, as it places the subject on a higher plane with the general
aan and is a matter of immense importance to humanity.
aking the work in its entirety it is a valuable contribution to
the subject, and can’t fail to be useful to the student beginner
as well as to entomologists in general.”—utomological News.
“To many readers, especially to those who, whilst studying
Ly one order, want a clear explanation of the general
eharacter and biology of the other orders, the book must bea
precious boon, from which the fact that the illustrations are
taken from American insects detracts nothing. Dr. Kellogg has
long undoubtedly been in the first rank of American entomolo-
ee and this latest work can only add lustre to an already
istinguished name.’—/. W. Tutt in Entomologist’s Record
(London).
FENRY HOLT AND COMPANY
PUBLISHERS New York
AMERICAN NATURE SERIES
THE FRESHWATER AQUARIUM
AND ITS INHABITANTS
A Guide for the Amateur Aquarist. By Orro Eaqe.ine and
FREDERICK EHRENBERG.
With 100 illustrations from photographs, large 12mo, 352 pp.
$2.00 net; by mail, $2.19.
A freshwater aquarium is far easier to maintain than either
birds, plants, or domestic animals. It opens to easy observation
a world of interesting plants and the locomotion, manner of feed-
ing, of escaping from enemies of play, battle, and courtship of a
multitude of creatures whose ways of life are entirely different
from those of terrestrial organisms.
This volume gives clear and complete instructions to the ama-
teur. It describes and illustrates by some of the finest photographs
ever taken from life, the great variety of plants, fishes, turtles,
frogs, and insects that may be kept indoors in health and content-
ment. It furnishes information concerning food, treatment in
health and sickness, methods of capture and handling, and what
aquatic creatures will or will not live in peace together.
CONTENTS
I. The Aquarium.
II. Aquarium Plants.
III. The Inhabitants of the Aquarium.
IV. The Feeding of the Inmates of the Aquarium.
V. Fish-hatching in the Aquarium.
VI. Fish Maladies,
VII. Implements for the Care and Keeping of the Aquarium.
“The best guide to the aquarium.”—The Independent.
HENRY HOLT AND COMPANY
Publishers . New York
By DAVID STARR JORDAN
A GUIDE TO THE STUDY OF
FISHES
2 volumes, 934 illustrations. 1223 pp. $12.00 net, postage extra.
32-pp. Prospectus on application.
A comprehensive work, at once scientific and popular, by the lead-
ing American ichthyologist. It discusses the structure, habits, evo-
lution, and economic value of fishes. It treats of the characteristics
of chief groups, emphasizing those which by reason of divergence
from typical forms are of especial interest. Extinct fishes are dis-
cussed along with their living relations. Nothing has been spared
to make the work, in illustration and mechanical execution, worthy
of a magnum opus. There is an abundance of pictures in half-tone
and other forms of black-and-white illustration, and the frontispiece
of each volume shows in colors some of the remarkable fish brought
by the author from his Pacific explorations. There are also portraits
of the world’s leading ichthyologists,
“The most comprehensive treatise on American Ichthyology.”’— The Dial.
“The first large work on fishes to be independently undertaken by the writer,
is of nearly twice the extent of Guenther’s ‘Introduction’ or of the ‘Cambridge
Natural History’ and like them ‘ treats of the fish from all points of view.’ . . .
The author has given us the cream of his long experience and wide knowledge of
American fishes and has made it full and attractive. There is no other account of
the sort for American readers.” —Jacob Reighard in Science.
FISHES
American Nature Series. '789 pp., 671 illustrations, 18 color plates.
$6.00 net, carriage 50 cents.
This book includes virtually all the non-technical material contained
in the author’s larger work, ‘‘ Guide to the Study of Fishes.” The
fishes used for food and those sought by anglers in America are treat-
ed fully, and proportionate attention is paid to all the existing, as
well as all extinct families of fishes. Notwithstanding the relative
absence of technical material, it is expected that the book will be of
value to students of ichthyology. Its chief aim, however, is to be of
interest to nature-lovers and anglers and instructive to all who open
its pages.
‘* Of the highest value for the intelligent reader. An authoritative treatise and a
readable essay.”,— Boston Transcript.
‘¢The author’s wide knowledge of this group of animals, his comprehensive
selection of interesting data, his terse, lucid, often humorous presentation, all com-
bine to make this by far the most readable and interesting popular natural history
of fishes.”"— Zhe Dial.
HENRY HOLT AND COMPANY
PUBLISHERS NEW YORK
LATEST VOLUMES IN ©
THE AMERICAN NATURE SERIES
(Prospectus of entire Series on request)
INSECTS AND DISEASE
By R. W. Doane, of Stanford University. Illustrated.
$1.50 net; by mail, $1.62.
“ Describes lucidly and entertainingly, in language that all may under-
stand, the discoveries in the disease-bearing qualities of insects, the suc-
cessful fights that have been made in consequence against yellow fever,
malaria and plague, and the present state of the investigations.”’—New
York Sun.
THE CARE OF TREES IN LAWN, STREET, AND PARK
By B. E. Fernow, of the University of Toronto. Illus-
trated. $2.00 net; by mail, $2.17.
Written for amateurs by a forester, this volume furnishes information
such as the owner of trees or the “tree warden” may need.
“Truly admirable . . . eminently practical. . . . His list of trees
desirable for shade and ornament is a full and most valuable one, and
the illustrations are enlightening.”—New York Tribune.
HARDY PLANTS FOR COTTAGE GARDENS
By Heten R. AxseE, Author of “ Mountain Playmates.”
Illustrated. 12mo. $1.60 net; by mail, $1.75.
“‘Eminently practical and well arranged. . . . Lists giving manner of
growth, height, time of blooming, exact color, special requirements of
soil and moisture are provided, and proper classifications and indexes
make the book one of the most valuable yet offered to the garden
grower.”’—Boston Transcript.
SHELL-FISH INDUSTRIES
By James L. Ke ttocc, of Williams College. Illustrated.
$1.75 net; by mail, $1.91.
“Interests all classes, the biologist, the oyster grower, the trader and
the eater of oysters. The whole book is very readable.”—New York Sun.
FISH STORIES: Alleged and Experienced, with a Little
History, Natural and Unnatural
By Caries F. Hoiper and Davin Starr JorpAN. With
colored plates and many illustrations from photographs.
$1.75 net; by mail, $1.87.
“A delightful miscellany, telling about fish of the strangest kind.
Nearly everything that is entertaining in the fish world is touched upon
and science and fishing are made very readable.’—New York Sun.
INSECT STORIES
By Vernon L. Kettoce. Illustrated. $1.50 net ; by mail, $1.62.
“The author is among a few scientific writers of distinction who can
interest the popular mind. No intelligent youth can fail to read it with
delight and profit.”—The Nation.
HENRY HOLT AND COMPANY
PUBLISHERS NEW YORK
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Insects and Disease
Doane, Rennie W.
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